/sqt/ /qtddtot/ - stupid questions thread

[Anonymous No.15790245]

Formerly: >>15770980

>what is /sqt/ for?
Questions regarding maths and science. Also homework.
>where do I go for advice?
>>>/sci/scg or >>>/adv/
>where do I go for other questions and requests?
>>>/wsr/ >>>/g/sqt >>>/diy/sqt etc.
>how do I post math symbols (Latex)?
rentry.org/sci-latex-v1
>a plain google search didn't return anything, is there anything else I should try before asking the question here?
scholar.google.com
>where can I search for proofs?
proofwiki.org
>where can I look up if the question has already been asked here?
warosu.org/sci
eientei.xyz/sci
>how do I optimize an image losslessly?
trimage.org
pnggauntlet.com
>how do I find the source of an image?
images.google.com
tineye.com
saucenao.com
iqdb.org

>where can I get:
>books?
libgen.rs
annas-archive.org
stitz-zeager.com
openstax.org
activecalculus.org
>articles?
sci-hub.st
>book recs?
sites.google.com/site/scienceandmathguide
4chan-science.fandom.com/wiki//sci/_Wiki
math.ucr.edu/home/baez/physics/Administrivia/booklist.html
>online courses and lectures?
khanacademy.org
>charts?
imgur.com/a/pHfMGwE
imgur.com/a/ZZDVNk1
>tables, properties and material selection?
www.engineeringtoolbox.com
www.matweb.com
www.chemspider.com

Tips for asking questions here:
>attach an image (animal images are ideal, you can grab them from >>>/an/. Alternatively use anime from safebooru.donmai.us)
>avoid replying to yourself
>ask anonymously
>recheck the Latex before posting
>ignore shitpost replies
>avoid getting into arguments
>do not tell us where is it you came from
>do not mention how [other place] didn't answer your question so you're reposting it here
>if you need to ask for clarification fifteen times in a row, try to make the sequence easy to read through
>I'm not reading your handwriting
>I'm not flipping that sideways picture
>I'm not google translating your spanish
>don't ask to ask
>don't ask for a hint if you want a solution
>xyproblem.info

[Anonymous No.15790264]

>>15790245
1. How reliable are modern IPCC ARs and climate models?
I've recently read that as much as 4°C may be baked in at this point, in which case I doubt anything can adapt - is this true?
2. Can you eat Azolla?

[Anonymous No.15790492]

Why F=ma not a=F/m?
Doesn't force cause acceleration, not the other way around?

[Anonymous No.15790495]

>>15789945
>if the wire is ideal, the charges cant be losing momentum. and if they cant lose it, they cant be gaining it either
This is, again, only true in a steady state view of just the conductor. And even then, it is only true when the conductor has reached a steady state. Take an ideal conductor and apply a voltage to it. Obviously, there is a field within the wire the moments before steady state, which is at the very least limited by the speed of light even in ideal conductors. Now, the same thing happens when you close a circuit. Except in a circuit, the constant flow prevents the conductor from ever reaching equilibrium. I mean, what is even the model you are suggesting here? You have constant moving charges, which have fields, which move other charges. How would the field ever be zero?

But I’ll restate the simpler and more fundamental question you seem to have missed, how could you ever have constant flow through a circuit with non-zero resistance and zero electric field?

[Anonymous No.15790538]

>>15790264
> in which case I doubt anything can adapt - is this true?
Life can adapt if given the time. It has in the past when the world was much hotter than it is today. But those changes happened over geological timescales, a million years instead of the handful of years we are seeing right now. Who knows what will actually happen but the effects could be brutal.

[Anonymous No.15790540]

>>15790245
is the sci guide ever going to go back up? the sites been down for months, does anyone have a mirror?

[Anonymous No.15790543]

>>15790492
You are being stupidly pedantic. It's an equation, you can rearrange it to fit whatever purpose you need to use it for depending on the known inputs.

[Anonymous No.15790547]

>>15790543
What's so pedantic about input being on the right side and the result on the left side? It's the only way. Acceleration never "causes" force. It is force that causes acceleration. So clearly the main form should be a=F/m. Of course you can rearrange it for the sake of solving for any variable. But it is not the point.

[Anonymous No.15790549]

How do I convince ChatGPT to stop apologizing? I tried asking repeatedly, in a strong language, and it stops for a second but then starts apologizing again once I ask a new question.

[Anonymous No.15790552]

>>15790547
What makes you think the input has to be on either side? You could measure the acceleration but not know the force, or vice versa, or even you know both but not the mass.

[Anonymous No.15790565]

>>15790552
>You could measure the acceleration but not know the force, or vice versa, or even you know both but not the mass.

Yes ,like I said, I understand that one can solve for any unknown by rearranging the original expression. For example in case of the Ohm's law, anything can be thought to "cause" anything else, I,V,R. But Newton's second law of motion states that force causes acceleration which is the same as writing a=F/m. Not F=ma. F=ma would mean that force is a property of an accelerating object of mass m. That somehow by accelerating it we "create" force. That is misleading. F=ma looks it has been rearranged to solve for F, specifically. But that's not what happens in nature.

[Anonymous No.15790571]

>>15790565
> But Newton's second law of motion states that force causes acceleration
It doesn't state that at all. Newton in the Principa actually worded it as follows:

> The rate of change of the momentum of a body is directly proportional to the net force acting on it, and the direction of the change in momentum takes place in the direction of the net force.
Which if you write it in modern mathematics is [math]F = \dfrac{d}{dt} (mv) = ma[/math].

[Anonymous No.15790573]

>>15790495
>And even then, it is only true when the conductor has reached a steady state. Take an ideal conductor and apply a voltage to it. Obviously, there is a field within the wire the moments before steady state, which is at the very least limited by the speed of light even in ideal conductors. Now, the same thing happens when you close a circuit.
this kind of sounds like what i was saying here >>15789018 ("if the charges started "stationary" and began to migrate down the conductor once the circuit was closed, then you can reason that at some point there must have been a field in the wire, but macroscopically, statistically, theres none.")
>Except in a circuit, the constant flow prevents the conductor from ever reaching equilibrium.
im not sure what you mean by equilibrium, but it definitely reaches a steady state. quite quickly, usually.
>how could you ever have constant flow through a circuit with non-zero resistance and zero electric field?
like pic related. notice that the field is the negative derivative of voltage (definition of voltage), so the flat parts of the voltage graph imply zero field in those sections of the circuit. theres a bulk field in the resistor, because the charges do in fact "pile up" in the resistor and create the field necessary for the charges to get through it, but no such bulk field exists in the ideal conductor. its like if you were driving your car down a frictionless road (and i guess your car is frictionless as well), and every once and a while you drive across a patch of road that did have friction. in order to drive at a constant speed the whole time, the engine would need to propel the car forward while it was on the friction patches, but it would need to do nothing while it was on the frictionless portions.

[Anonymous No.15790586]

>>15790571
>>...and the direction of the change in momentum takes place in the direction of the net force.
>doesnt use the little vector arrows
smdh damn head

[Anonymous No.15790748]

>>15790571
>B (the result) is proportional to A (the cause)
In other words B=A
But Newton has written it backwards.
This whole d/dt mv should be on the left and = F, since F is the input. Imagine the body m is minding its own business and is resting or moving with constant v. Then boom! Force was applied to it.
So F should be on the right side.

Newton was retarded.

[Anonymous No.15790749]

>>15790492
Mass and acceleration are properties of the particle, force is a property of something external. Hence F = ma. Force is directly measurable with balances and spring scales.Sum of external forces equals resultant change in momentum, F1 + F2 = ma = mdv/dt = dp/dt. Rewriting a as dv/dt gives
integral(F)dt = integral(m)dv
impulse = change in momentum
in absence of external forces, a system's momentum is constant
rewriting a = (dv/dt)(ds/ds) = (ds/dt)(dv/ds) = v(dv/ds) gives
int(F)ds = int(mv)dv
Work = change in kinetic energy
in absence of tangential forces, KE is constant
in absence of non-conservative forces, KE + PE is constant
F = ma works too well to have it any other way.

[Anonymous No.15790809]

>>15790749
What about gravity? Is it a force or does it create a force? g has the same units as a, and F=mg. So what causes what in this case? By analogy, it would mean that F causes g? It doesn't make sense.

[Anonymous No.15790877]

>>15790809
Gravity is a phenomenon of mutual attraction between massive onjects, if you want to know what causes it, you have to ask the theoretical physicists. Experimental evidence supports Einstein's theory of general relativity to describe its behavior, but for human to earth sized scales, a simplification to Newton's theory F_grav = G(m1)(m2)/r^2 is usually pretty accurate. A further simplification can be made if your scenario involves objects around human scale at sea level. In this case G = gravitational constant, m2 = mass of earth, r = distance from m1 to m2(hypothetical center of mass of earth) are all fairly constant, so all those terms get wrapped up into g = 9.81m/s^2. This lowest level simplification is then F_grav = mg. It is not very revealing about the nature of the universe, but it makes calculations very simple.
The real head scratcher is why does the property of 'mass' both contribute to gravitational force and inertial force (resistance to change in inertia)?

[Anonymous No.15790926]

Suicide suicide suicide

[Anonymous No.15791167]

the domain of f is X(0,2) and range Y(0,1)
how do i find the domains and ranges of these?

[Anonymous No.15791179]

>>15791167
For h(x), keep in mind that if f maps from X to Y, its inverse will map from Y to X.
For g(x), you know the values you are allowed to plug into f(x), and you know the values it will spit out. You also (should?) know that ln(f(x)) means that you are plugging the outputs of f(x) directly into ln. What values can ln return on the range of f(x)?
and then you can apply the reasoning behind both of the above to u(x)

[Anonymous No.15791292]

Could someone help me with this? The earlier assignments were relatively chill statisticial and probability stuff, but this seems a bit more "out there" with the technical language and stuff.

Any help would be appreciated.
(Also it's Cola, not Toffee, dunno why the translator scuffed it)

[Anonymous No.15791560]

I really only need e, but it should be coercive right? Seems pretty simple since the vector x's magnitude goes to infinity, but I saw something online about the direction of the vector and wasn't sure if this affected it being coercive or not.

By the way I got coercive, not coercive, coercive, coercive if anyone wants to bother correcting any of these if they're wrong

[Anonymous No.15791585]

>>15791560
Only a is coercive.
Try looking at the level sets of the functions.
https://en.wikipedia.org/wiki/Level_set
If a function has an unbounded level set it can't be coercive.

[Anonymous No.15791589]

>>15790877
So gravity g is a field, just like E.
Compare: F=ma and F=mg.
a and g have the same units. But F=ma means that an external force "causes" acceleration. But F=mg would mean the opposite: when m is put into the field g, the field will exert a force on m. And g is really GM/r^2 so mass seems to be "the cause" of g. And when another mass is present, it experiences a force. In this case Force is the result. But in case of F=ma, the result is acceleration *due* to force. Do you see how everything is convoluted and chicken and egg can be swapped? If we have F=ma we can say that Force creates acceleration. But F=mg doesn't mean Force creates gravity. It means gravity creates force. Due to mass.

[Anonymous No.15791597]

>>15790549
I tried but to no avail.

[Anonymous No.15791607]

>>15791589
g isn't gravity. F is the force of gravity. g is the acceleration caused by the force of gravity.

[Anonymous No.15791613]

>>15791607
https://en.wikipedia.org/wiki/Gravity_of_Earth

[Anonymous No.15791650]

Why is this true? I mean looking at the graph of the function it's obvious but I don't get how I was supposed to realize it in the first place

[Anonymous No.15791661]

[math]\int_{0}^{2\pi} \frac { |\sin t| } { \sqrt{ 1 - \cos t } } = \int_{0}^{\pi} \frac { |\sin t| } { \sqrt{ 1 - \cos t } } + \int_{\pi}^{2\pi} \frac { |\sin t| } { \sqrt{ 1 - \cos t } }[/math]
[math] = \int_{0}^{\pi} \frac { |\sin t| } { \sqrt{ 1 - \cos t } } - \int_{2\pi}^{\pi} \frac { |\sin t| } { \sqrt{ 1 - \cos t } }[/math]
can't be assed to work out the formal argument here, but because sin and cos are periodic with respect to 2π, the integral from 2π to π is basically the negative of the integral from 0 to π (since it's just going in reverse)

[Anonymous No.15791666]

Both ChatGPT and Bard are fucking annoying and retarded and give confusing explanations, contradict themselves, hallucinate, flip-flop, lie, and apologize. They are only good at answering simple questions that do not require detailed explanations. The only reasonable answers that I find on the web are answered by humans. AI is shit. Some say give it some time, it is improving quickly. I don't notice much progress.

[Anonymous No.15791709]

>>15790538
I'm afraid they'll most likely be catastrophic.
I just don't know what to think about it. On the one hand, I do hope that the human race can survive what's coming. On the other hand, I can't help but feel melancholic when thinking about temporality of our civilization.

[Anonymous No.15791721]

>>15791597
Okay, try telling it random statements. That is,
every prompt you make to it does not relate to
the last and the subject matter changes too.
Literally David Byrne that shit. Continue until
it stops apologizing and you can return to
normal, or just turn off the chat and let it rest.

[Anonymous No.15791941]

>>15790245
Let [math]X[/math] be a topological space with open cover [math]U_i.[/math] Let [math]K[/math] be a subset of [math]X[/math] such that for each [math]i[/math], [math]K \cap U_i[/math] is closed in [math]U_i[/math] (with the subspace topology). Is [math]K[/math] closed in [math]X[/math]? What if the [math]U_i[/math]'s make a finite cover?

[Anonymous No.15791964]

>>15791650
>Even function (such as cos(x)) :
E(-x) = E(x)
integral[E(x)] -a -> +a = 2*integral[E(x)] 0 -> +a
provided the integral converges everywhere on [-a,a]
>Odd function (such as sin(x)) :
O(-x) = -O(x)
integral[O(x)] -a -> +a = 0

In your problem, the limits aren't symmetric about 0, but red flags should go up if you see trig functions and limits across a full or half period, [0, 2pi], [pi, 2pi], etc. The intuition for this problem comes from seeing the rough shape of sin and cos in your head, then the rough shape of |sin(x)| and sqrt[1-cos(x)], seeing that they're all oddly or evenly symmetric about x = pi, then reasoning/visualizing that the full function must be too. If you have to show work, just make the substitution u = pi - x and phase shifts to get everything centered around 0.

[Anonymous No.15792033]

>>15791709
It's a self regulating system. Most of humanity dies due to climate change because we're mostly a bunch of selfish idiots. All the shit we've been doing stops or drops markedly. The Earth eventually recovers and life carries on.

[Anonymous No.15792083]

>>15790245
Hey guys, sorry for the dumb question. Doing chemistry homework and quantum numbers, and just need someone to tell me if my answer is correct. It's imperative I get this question right.

[Anonymous No.15792092]

>>15792033
I suspected as much too desu.
However, will the civilization recover? Or at least will it exist in some form?

[Anonymous No.15792099]

>>15792083
Almost, but not quite. Remember that [math]m_l[/math] cannot be [math]-1[/math] when [math]l=0[/math] so that rules out that possible state.

[Anonymous No.15792100]

>>15792083
You know all the quantum numbers except l. l can be 1, 2, 3 (it can't be zero since m_l is non-zero). So I count three.

[Anonymous No.15792102]

>>15792092
Now you're asking an impossible to answer question because there are too many what-ifs.

[Anonymous No.15792119]

>>15792102
Well, then I guess we'll have to live long enough to find out the answer.
What are your thoughts on it though?

[Anonymous No.15792130]

>>15791589
Youre just repeating yourself

[Anonymous No.15792131]

>>15792099
>>15792100
So now would this be correct? Thank you guys for the help, quantum numbers always fuck with me man

[Anonymous No.15792140]

>>15792131
this is the answer I got from chegg, I'm assuming it's wrong but I thought I should post it here for you all

[Anonymous No.15792149]

>>15792140
> expert answer
some expert.

[Anonymous No.15792241]

Thoughts on the UFO stuff ( David gursch)?

More Bs or plausible?

[Anonymous No.15792245]

>>15792241
More bullshit. It's always bullshit.

[Anonymous No.15792249]

>>15792245
I don't disagree. It's all bs until real tangible proof can be found and studied. But the guy has not really asked for money and his background does check out. That has to count for something no?

[Anonymous No.15792258]

>>15792249
It counts for nothing. If there was ever clear evidence it would be incontrovertible. There would be no need to ask if it was real or not. But of course that never happens.

[Anonymous No.15792261]

Is there a trivial amount of sugar in black coffee?
When I boil down black coffee, it has a bit of the qualities of syrup. I want it to be as close to a powder as possible. I want to know if this is because of a sugar content or because of something else in the coffee.
I'm doing this because I want to use it as pigment in paint/ink/stain and it will be beneficial to me if it has as little qualities of a syrup/sludge as possible. If it's sugar then I want to use yeast to remove it.

[Anonymous No.15792278]

What is the true cause of engine knock/pre ignition? The common way I’ve always heard it explained was like a gasoline engine accidentally working like a Diesel engine from pressure. But apparently this is wrong and engine knock always occurs after initial first spark, with something to do with multiple flame fronts?

[Anonymous No.15792558]

Getting filtered hard by Real Analysis bros. Don't know if it's just low IQ or bad study habits but I'm struggling to keep up. How were you anons successful in higher math? What did you do?

[Anonymous No.15792579]

where the fuck is he getting -4 and -2 from in the x column. i never understand these questions. do you just choose x values at random?

[Anonymous No.15792694]

>>15792579
> do you just choose x values at random?
sometimes, but in this case he is choosing values for x such that y is positive and negative, so you can see where it crosses the y-axis.

[Anonymous No.15792698]

>>15792579
looks like it. Normally, with a clean parabola like that, you just see that x = 3, -3 will make y = 0, and get those two freebies.

[Anonymous No.15792742]

If X and Y are correlated, and X and Z are correlated, does that imply Y and Z are correlated?

[Anonymous No.15792755]

How do I pirate a paid account on UpToDate? Some free mirror of it somewhere?

[Anonymous No.15792760]

>>15792742
Yes, it's literally what the phrase "correlation does not mean causation" arises from. If X is the cause but you only measure the correlation between Y and Z you might concluded an incorrect cause/effect relationship.

[Anonymous No.15793159]

Consider the complex matrix [eqn]\begin{pmatrix} a & b \\ -b & a \end{pmatrix}.[/eqn]I want to show that this matrix is diagonalizable for all complex a and b. It's trivial in case of [math]b = 0[/math] and when [math]b \neq 0[/math], I found the two eigenvectors [math](i,\, 1)[/math] and [math](-i,\, 1)[/math] that form a basis of [math]\mathbb{C}^2[/math].

That's my explanation. Did I miss something or make a mistake?

[Anonymous No.15793175]

>>15793159
Those vectors are only eigenvectors for some choices of (a,b). Calculate the eigenvalues that is the roots of the characteristic polynomial. If an nxn matrix has n distinct eigenvalues then you know it's diagonalizable.

[Anonymous No.15793180]

>>15793175
I calculated the eigenvalues [math]a - ib[/math] and [math]a + ib[/math] and apparently these are equal, if and only if [math]b = 0[math]. Because [eqn]
\begin{align*}
a - ib &= a + ib &\iff\\
-ib &= ib &\iff\\
-b &= b &\iff\\
b &= 0
\end{align*}
[/eqn]If you apply Gauss, then you end up with the eigenvectors here: >>15793159.

Can you give me an example for a complex a and a complex, non-zero b, such that the eigenvectors are not (i, 1) and (-i, 1)?

[Anonymous No.15793183]

>>15793159
if b = 0 then the matrix is already diagonal. If b =/= 0, then the polynomial P(X) := (X - a - b*i) (X - a + b * i) = X^2 - 2aX + (a^2+b^2) has two distinct roots and P(M) = 0 where M is your matrix. Hence M is diagonalizable.

[Anonymous No.15793247]

>>15792558
if it makes you feel any better, it's a very common opinion that real analysis is the first proper filter in mathematics

[Anonymous No.15793311]

>>15793175
>Those vectors are only eigenvectors for some choices of (a,b)
This is incorrect. Any matrix having that form has [i,1] and [-i,1] as eigenvectors. The values of a and b only affect the eigenvalues.
[eqn]
\begin{pmatrix} a && b \\ -b && a \end{pmatrix}\begin{pmatrix} i \\ 1 \end{pmatrix} = \begin{pmatrix} b+ai \\ a-ib \end{pmatrix} = (a-bi)\begin{pmatrix} i \\ 1 \end{pmatrix} \\
\begin{pmatrix} a && b \\ -b && a \end{pmatrix}\begin{pmatrix} -i \\ 1 \end{pmatrix} = \begin{pmatrix} b+ai \\ a-ib \end{pmatrix} = (a+bi)\begin{pmatrix} -i \\ 1 \end{pmatrix}
[/eqn]

[Anonymous No.15793317]

>>15793159
[eqn]
\begin{pmatrix} i && -i \\ 1 && 1 \end{pmatrix}\begin{pmatrix} a-bi && 0 \\ 0 && a+bi \end{pmatrix}\begin{pmatrix} i && -i \\ 1 && 1 \end{pmatrix}^{-1} = \begin{pmatrix} a && b \\ -b && a \end{pmatrix}
[/eqn]

[Anonymous No.15793458]

if we have f(x) = x^2 and we know that limf(x) = 4 as x approaches 2, if epsilon= 5, what is the highest value of delta?
I got that the values for x that would satisfy the inequality l x^2-4 l < 5 are 0 and 1, but if I plug them into l x-2 l, the highest value would be if x = 0 so l -2 l = 2 so delta woud have to be greater than 2, but the answer says that delta=1, what am I missing?

[Anonymous No.15793596]

I have some data, I get some order 3 polynomial fit with R^2=.91
So this tells me how good of a correlation I have between x and y while using that polynomial (for a specific x interval ofc).
But what I actually want is the derivative. Surely the accuracy of the correlation between x vs dy/dx is going to be substantially lower than for x vs y. Is there a way of modifying the R^2 value of the fit to get the R^2 value of its derivative?
Calculating the slope from the data directly produces some really noisy shit, so I'm not sure fitting that instead and getting an R^2 value that way is really a good idea.
I'm not good in stats, help.

[Anonymous No.15793632]

Okay, I'm probably just really dumb, but I cannot figure out why my calculations do not add up.
I have two walls (the leftmost and rightmost timbre), 15.48 meters apart. In between them, I need to put 14 timbers spread out evenly. The timbers have a width of 0.16m. With this, accounting for their width, I've figured out that the gap between them should be 0.952m each. Multiplied with 15 gaps this means that the total gap space is 14.28 meters. However, when I take the total timbre width, which is 16*14 equals 224 cm or 2.24 meters. Subtracting this number from the total distance between the walls, results in the total gap space of 13.24m, which gives me a gap distance of 0.882~.

What am I doing wrong?

[Anonymous No.15793647]

>>15793632
>>15793632
>this means that the total gap space is 14.28 meters
15.48-14.28=1.2
1.2/14=.086 =/= .16, definitely something wrong here.
You measured .952m using blender or something? Not sure but I think the spacing isn't even and/or its not measuring from the edges of the beams on both sides or some such issue.

[Anonymous No.15793659]

>>15793647
>You measured .952m using blender or something?
No, I'm only using it to visualise.
15.48 / 15 = 1.032m; I subtract half of the timbre width (0.08) to get 0.952m for the two beams next to the walls. The rest between them then get subtracted another half to get us to 0.872m.
This however means that they aren't evenly spaced. So it's probably not the way to go about it.

[Anonymous No.15793668]

>>15793659
Well yeah in this case your effectively centering your beams with the 15 spacing increments, so they can't be evenly spaced. If you want even spacing you need to include the edges of the beams at both ends.
So 15.48+(.08)x2=15.64. Now all 15 spaces are bounded with two beam edges of length .08. So
15.64/15=1.04267m increments. 1.04267-.08*2=.88267, same result you get with the way less pointlessly tedious method.

[Anonymous No.15793671]

>>15793668
Oh yeah, it suddenly makes all so much sense. I feel even stupider than before.
Thanks!

[Anonymous No.15793674]

>>15793668
here's some crayons

[Anonymous No.15793902]

>>15790245
i still dont understand why reversing direction in ac currents is important. All the definitions through google searches say this but dont really explain why its important and why that leads to ac currents being more efficient than dc currents. Does reversing direction mean the power source is turning off and on? If that so would this cause power fluctuations?

ive taken calc based physics classes so dont hold back. im just super confused.

[Anonymous No.15793917]

>>15793902
To have an electric grid that transports electricity across great distances you want high voltages so the power loss is low. So that means you need transformers. Because the principle behind transformers only works with AC it is the best choice for that task. You can do the same with DC using capacitors and diodes but that is much more complicated and costly. AC transformers to step-up and step-down voltages are simple to build and highly efficient. DC is better for other things but not that.

> Does reversing direction mean the power source is turning off and on? If that so would this cause power fluctuations?
Yes which is why we use three-phase power transmission so it is never zero (the RMS power law).

[Anonymous No.15793940]

>>15793917
and im guessing they do something in the powerlines that makes it so that volts and amps are inversely proportional so less power is lost to heat?

[Anonymous No.15793941]

>>15790245
What is the best way to achieve pic rel?
All the other pseudocode crap are too restricting, this is just text aligned in a specific way.

[Anonymous No.15793944]

>>15793941
*just to clarify, I am talking about how write it in latex. Book source is combinatorial optimization - Bernhard Korte, Jens Vygen.

[Anonymous No.15793957]

>>15793940
Correct. That power loss is proportional to the current squared. So minimizing the current is of huge benefit which can be achieved by stepping up the voltage.

[Anonymous No.15793964]

>>15793957
that's neat. humans are clever

[Anonymous No.15794043]

i'm reading about the total differential and finally realized I have no idea what the dx, dy, dz notation means. I know what dy/dx means, but it starts to get confusing when you start throwing them around standalone, like dz = fxdx + fydy. What does dx or dy mean in this context?

[Anonymous No.15794045]

is it safer/easier to shit underwater, due to equalization of pressure? Asking because hemorrhoid

[Anonymous No.15794046]

>>15794043
never mind it all makes sense now

[Anonymous No.15794051]

>>15793941
>>15793944
Latex is hilariously bad at achieving this effect. Here is one way:

$\begin{array}{l}
\mathbb{For}~ j := 1~mathbb\{to}~n~\mathbb{do}: \\
~~~~~~~~~ \mathbb{For} ….etc
….etc
\end{array}$

[Anonymous No.15794061]

Does continuity implies differentiability at at least one of the points in the domain?

[Anonymous No.15794081]

>もしもし, korewa 4chan clinic desss, watashiwa Dr. Faggotron desssssssss, how may I assist you
An area "behind" my nose (sinus/upper throat???) feels really dry and full of mucus, and I've been "snorting" really heavily since Friday to try to clear it out...
It's not a good feeling while I'm trying to code and study, and when my dorm apartment roommate comes back on Monday the unpleasant noise may be a problem.
What do you think this is, doc, some sort of infection or random allergy flareup? What should I buy for this, いしゃsan?

[Anonymous No.15794110]

The weierstrass function is continuous rverywhere but differentiable nowhere.

[Anonymous No.15794139]

>>15794061
in the realm of the hyperreals, yes

[Anonymous No.15794143]

>>15794081
sounds like a sinus infection. Could be a common rhinovirus, could also be the latest coronavirus, which acts mostly like a rhonovirus (I should know—I had it last week)

[Anonymous No.15794230]

>>15794061
no https://en.wikipedia.org/wiki/Weierstrass_function

[Anonymous No.15794432]

Regardless of anything that makes this a stupid exercise,
If you took the raw numbers of calories that account for overweight/obesity in the world, and distributed them among the amount of people that are starving in the world, would starvation be fixed?

[Anonymous No.15794437]

>>15794061
no, https://en.wikipedia.org/wiki/Blancmange_curve

[Anonymous No.15794438]

>>15794432
No, you are just delaying how long it will be before they begin to starve again.

[Anonymous No.15794439]

>>15794432
Not really

[Anonymous No.15794498]

>>15791292
Anyone?

[Anonymous No.15794538]

If I want to do least square method on the capacitance, and then I want to find epsilon r, how would I do that exactly? I've written a program to find k and m but I'm not sure what really is k and m, I know that y = C, x = 1/d, but what is A and epsilon 0/epsilon r?

[Anonymous No.15794570]

>>15794438
? the calories are perpetual

[Anonymous No.15794621]

>>15794570
Why do we need to eat then?

[Anonymous No.15794844]

Let's say I have some function f(x,y) where x and y enter f() multiplicatively. Is [math]\frac{\partial f}{\partial x} = \frac{\partial f}{\partial xy}y[/math]? I'm reading a proof where the starting formula has a derivative wrt xy but the result has a derivative wrt x in it so I'm wondering if this is what happened.

[Anonymous No.15794879]

>>15794844
[math]\frac{\partial}{\partial xy}[/math] isn't a valid expression. [math]\frac{\partial^2}{\partial xy}[/math] is, and so is [math]\frac{\partial}{\partial x}y[/math] but not what you wrote. Did you or the book make a typo or have you misread something?

[Anonymous No.15794979]

>>15794879
I meant to say [math]\frac{\partial}{\partial(xy)}[/math]. In the actual proof, they start with an expression with [math]\frac{\partial f}{\partial z}[/math] and the next line is an expression with [math]\frac{\partial}{\partial x}[/math]. But z takes a z = xy form hence my rewriting. They don't explain the derivative change but I manage to go from one line to the other by using [math]\frac{\partial f}{\partial x} = \frac{\partial}{\partial(xy)}[/math] in one of the steps, so I'm wondering if that's really what they might've done.

[Anonymous No.15795036]

>>15794979
I would assume they are doing something with the total derivative.

[Anonymous No.15795050]

how does my proof look for f is surjective iff f has right inverse?

[Anonymous No.15795058]

>>15795050
>f is surjective iff f has right inverse
Impossible to prove unless you believe in the "axiom of choice" which you shouldn't.

[Anonymous No.15795107]

>>15795058
>yeah bro not every finite subset of the natural numbers has a smallest element. That's hocus pocus

[Anonymous No.15795268]

lets say i have small motor that can power itself for 100 years

then lets say i use the motor to move a magnet up and down constantly. Next i put a copper coil next to this device. Will an induced current move through that coil for the full 100 years?

[Anonymous No.15795290]

>>15794621
i'm asking if you took the calories that account for overweight/obesity. fat people keep eating. why would i be asking about a single snapshot in time. you're a psycho

[Anonymous No.15795292]

>>15794621
a fat person eats more than they should. if you took the amount that every fat person eats over what they should, and distributed that amount over all the people starving, would the amount that fat people eat over what they should be greater than the amount people starving lack. is the question

[Anonymous No.15795379]

>>15790245
What're molecules really like
I know they arent just balls and sticks, but if atoms are just clouds of electrons around fucking tiny ass shits, of which we dont fully know if theyre solid or just what happens when 3 even smaller things get together and are maybe solid(?)
point is, what do molecules actually look like

[Anonymous No.15795446]

>>15795379
> what do molecules actually look like
You are talking about quantum objects. You need to be extremely careful and precise about what you mean by "look". Molecules are so small you can't even use visible light to see them since its wavelength is too long.

[Anonymous No.15795449]

>>15795446
The naked human eye can see individual atoms with special techniques. If you repeatedly divide material into layers, visually, over and over again eventually you can see tiny atoms that compose most things. It's not crystal clear and it's difficult to actually see (you can only see the proton and neutron not the orbiting electrons) but you can for small periods of time before your eye muscles fatigue from focusing.

I have used this before to repair very small things like electronics, motors, as well as to divide things from one another like fabric or food. I think it's because it's counterintuitive because you can't do it through a microscope because of the glass. Your eye cannot focus properly. You'd think you could see the atoms of the glass in that case but if you're right up against it you're too close for your eyes to focus.

[Anonymous No.15795453]

>>15795449
this is the thread for stupid questions, not the thread for stupid answers.

[Anonymous No.15795531]

Had to look up a guide for one of the Apostol questions and one of the steps fucks with me:

[eqn] a(S) = \int^{1-a}_0 (x - x^2 - ax) dx = (1 - a) \int^{1-a}_0 x dx - \int^{1-a}_0 x^2 dx [/eqn]

How the fuck did they distribute to this?

[Anonymous No.15795546]

I want to know the answer. I don't get how the rate r(s) works, which I assume is N number of particles released per second at time s. How do you determine the real number of particles released in one second knowing the initial number Ni? You can't plug it in anywhere. And also how do you make this equation sum up all the particles released without using a sum operation?

[Anonymous No.15795562]

>>15795446
Like, i dont give a fuck about color, or lack thereof, but rather the shape of a molecule, not in diagram form but in actuality. Like, how do the fucking electron fuzz of atoms mingle in a molecule, how do the different atoms' protons and neutrons interact or lack thereof? Sorry if its vague as shit because I genuinely feel like im not smart enough to ask the right questions

[Anonymous No.15795580]

Has there ever been a single scientific or mathematical discovery made by a palestinian? I'm trying really hard but I can't find a single accomplishment whatsoever

[Anonymous No.15795719]

>>15795562
>Like, how do the fucking electron fuzz of atoms mingle in a molecule, how do the different atoms' protons and neutrons interact or lack thereof?
Electrons attract nuclei. Eletrons repel other electrons, and nuclei repel other nuclei.
If you draw a free body diagram of all these attractive/repulsive forces, you find there's a "sweet spot" distance where the attractive and repulsive forces cancel out. The atoms neither fly apart, nor crash together. This is best illustrated with a Morse Potential diagram (picrel), which is how molecular bonds are formed.

As far as large molecules go, it's the same idea. Just a masive network of morse bonding potentials.

[Anonymous No.15795731]

>>15795562
(cont.)
Once the atoms are all bonded, you get what's called a "Linear Combination of Atomic Orbitals," (LCAO) where all the s, p, d, etc. orbitals combine into these big, complex, 3-dimensional Molecular Orbitals (MO). These behave similar to a harmonic series, where each successive energy level above the ground state adds a node to the wave function, so instead of a single solid cloud, the MO's get "pinched" into a semi-periodic series of lobes and nodes.

The locations and energy levels of each lobe, particularly in the HOMO (highest occupied) and LUMO (lowest unoccupied), is important for predicting reactivity. If you want to learn more, definitely check out Frontier Orbital MO theory.

[Anonymous No.15795734]

Let's say i want to learn maths from the beginning. Where do i start? Are there any sources i can use to learn it by myself online (The ones that actually work and are free&open source) Also any ebooks that are good?
Mostly need it for programming and compsci class

[Anonymous No.15795778]

>>15795531
yeah you can do that
[math]\int (f+g) = \int f + \int g[/math]

with some gay caveat about convergence

[Anonymous No.15795840]

>>15790245
Why does /sci/ let fat coomers be their science communicators?
https://www.youtube.com/watch?v=iwUmaCS6pjA

[Anonymous No.15795896]

>>15795734
Khan Academy.

[Anonymous No.15796031]

I am looking to implement a forward error correction scheme. In my first trial it worked great because my modulation method would only have errors of a few bits and by checking the hamming distance I would solve most errors!

With the modulation I have decided to use, hamming distance goes straight out the window! Is there anyway to do forward error correction without going to binary?
"The quick brown fox jumped over the lazy dog."
Sure, I could repeat it three times:
"The q__ck brown fox jufped over the l3zy dog."
"The quick broon f01 jumped over the lazy dog."
"The quick brown fox jumped ovea the lazy dog."
Sure, this solves single character errors. But not if something extra gets added. Any ideas frens?

[Anonymous No.15796051]

>>15795778
Yeah, but how do they turn [math]-ax[/math] into [math]{1-a}[/math]?

[Anonymous No.15796061]

>>15796051
You missed a term: [math]x - ax = x(1-a)[/math]

[Anonymous No.15796084]

>>15796031
The next problem is that even if I triplicate it, if there is letters added or subtracted it will screw over the next batch. So I need a header, the message, and a checksum.
Maybe I've gone crazy. But my new plan is to send every packet twice (it's a one way transmission the client can't ask for a resend). Add a checksum on the end. And then a checksum for the checksum. If there is a single error, it should be trivial to brute force the correct message? Yes? Or I have I lost my nut.

[Anonymous No.15796119]

If you're given a function in form of a power series, how can you extract from it the power series of its inverse?

[Anonymous No.15796249]

Thinking of setting off a high altitude balloon. What are some instruments besides tracking and cameras would you add? I was thinking of including a nice microphone. I'd use something like pic rel

[Anonymous No.15796373]

>>15796249
freon cannister, punctured

[Anonymous No.15796412]

>>15796249
You can also add FAA approval for that balloon

[Anonymous No.15796502]

>>15796119
[math] (f_0+f_1+f_2+...)^{-1} = f_0^{-1}(1+f_1/f_0+f_2/f_0+...)^{-1}=g_0+g_1+g_2+... [/math]
[math] g_0=1/f_0 [/math]
[math] g_1=-f_1/f_0^2 [/math]
[math] g_2=-f_2/f_0^2 + f_1^2/f_0^3 [/math]
etc.

[Anonymous No.15796504]

>>15796412
You are an idiot.

[Anonymous No.15796782]

can someone help me with an exercise in set theory?

Prove that if a function f maps A into A, and ran f = A, then f is injective

[Anonymous No.15796823]

>>15796782
The problem is wrong. Consider [math]A = \mathbb{R}[/math] and [math]f(x) = x^3 - x[/math] then [math]f(\mathbb{R}) = \mathbb{R}[/math] but the function is not injective as [math]f(-1) = f(0)[/math].

[Anonymous No.15796841]

>>15796823
Sorry I forgot to mention that A is finite

[Anonymous No.15797083]

>>15795449
Even if you had this jutsu, the dots you are seeing would be the cells in your eyes. And it's sparkly. And I recommend you take Lutein supplements.

[Anonymous No.15797142]

if 1^1 is 1 why isn't i^i just i?

[Anonymous No.15797186]

>>15797083
the cells in your eyes are too cclose to focus

[Anonymous No.15797188]

Can basic math (counting, addition, and subtraction) be written using only naive set theory and first order logic?

If it can be done, how would the answers be achieved?

[Anonymous No.15797212]

hey guys ive been stuck on part 2 of this problem for a while, pls help. ive sunk several hours into it
yes, im retarted

[Anonymous No.15797281]

>>15797212
https://proofwiki.org/wiki/Uniform_Limit_Theorem

[Anonymous No.15797285]

>>15797142
do you think 2^2 should be 2 as well?

[Anonymous No.15797300]

>>15797285
but isn't i basically just a perpendicular number line, with i being the imaginary number line's 1.
why should it act differently internally?

[Anonymous No.15797327]

>>15797188
stop jerking off and learn a real skill

[Anonymous No.15797386]

>>15797300
do you think i^2 should be i?
i may be represented as the unit of a number line perpendicular to the reals, but that doesn't mean that it will actually act like anything on the reals

[Anonymous No.15797430]

>>15797300
The perpendicular number line manifests in it a 90 degree rotation, so it does not act like the horizontal number line. The same way the horizontally flipped number does not work like the flipped number line.

[Anonymous No.15797486]

Am I retarded? Shouldn't that 0 be a 3?

[Anonymous No.15797548]

is the angle of the crescent moon the same everywhere on earth on a given day

for me, right now, the moon is a crescent on the bottom. will it be the same in asia in a few hours. will it be the same in the southern hemisphere.

[Anonymous No.15797604]

>>15797486
I don't recognize the notation. It can't be standard matrix vector multiplication since neither the book or your answer works.

[Anonymous No.15797609]

>>15797548
The moon shows one phase to the Earth at the same time (the crescent would be the same size), but different perspectives due to where you are on the globe will make the moon appear differently in the sky. For example in the northern hemisphere the sunlit part of the moon moves from right to left, while in the southern hemisphere it moves left to right.

[Anonymous No.15797634]

I'm in 2nd year of uni and I never learned how to factor polynomials, somehow I've yet to need it, I think it might be about time to learn it just in case, what is the quickest, best way to factor this for example?

[Anonymous No.15797642]

>>15797634
You'd start by asking yourself what two numbers multiply together to give 7.

[Anonymous No.15797660]

is the only time a relation an equivalence relation when it is the Cartesian product of the set on itself?

[Anonymous No.15797691]

>>15796782
>>15796841
For every [math] y \in A [/math], define [math] A_y := \{ x \in A : f(x) = y \} [/math]. Since [math] \operatorname{ran} f = A, |A_y| \geq 1 [/math] for every [math] y \in A [/math]. So [math] \{ A_y \}_{y \in A} [/math] is a partition of [math] A [/math] i.e., it is mutually disjoint and its union is [math] A [/math]. Therefore:
[eqn] |A| = \left| \bigcup_{y \in A} A_y \right| = \sum_{y \in A} \left|A_y \right| [/eqn]
from which it follows [math] \left|A_y \right| = 1 [/math] for every [math] y \in A [/math].

[Anonymous No.15797708]

>>15797386
Why do you keep asking me questions that have nothing to do with my question?
Or is the rule of the stupid questions thread that you can only answer with stupid questions?
>>15797430
Why does being flipped change how it behaves internally?

[Anonymous No.15797719]

>>15797708
Because they're not irrelevant to your question.
Your question is rooted in the assumption that i should behave just like 1 in a particular calculation. I'm asking you questions that show plenty of cases where i does not act like 1 at all. Why do you think that i should act like 1 in this particular case when it doesn't in any other?

[Anonymous No.15797721]

>>15797719
This. Why would you ever expect taking something to the i'th power to behave exactly the same as taking something to the power of 1 (doing nothing).

[Anonymous No.15797726]

>>15797719
but i^2 and 1^2i work exactly the same, why would you think i'd think i^2 is equal i?
>>15797721
because i'm not taking 1 to the power of i or i to the power of 1 i'm taking i to the power of i.
Why should the i number line work differently internally?

[Anonymous No.15797731]

>>15797726
You clearly don't know what is required to raise a number to a complex power.

[Anonymous No.15797733]

>>15797726
>but i^2 and 1^2i work exactly the same
They absolutely do not.

[Anonymous No.15797735]

>>15797726
>but i^2 and 1^2i work exactly the same

[Anonymous No.15797736]

>>15797731
>>15797733
Then why don't you guys just tell me why i'm wrong to begin with instead of playing games with me by asking silly questions?
just say "no you're wrong here's why."

[Anonymous No.15797740]

>>15797735
Why do you think I came to the stupid questions thread.
I knew the question was stupid i just didn't know why.

[Anonymous No.15797743]

>>15797736
>>15797740
Taking complex exponents is complicated. The answer would be long and non-trivial. It's hard to give an answer you would understand and not worth the effort when it feels like we are talking to someone who hasn't even taken an introductory class on complex numbers. Frankly save us all some time and just go Google your question and the answer.

[Anonymous No.15797746]

>>15797743
>someone who hasn't even taken an introductory class on complex numbers
Yes i haven't, i watched a single video and got curious. I didn't know being educated was needed to ask stupid questions in the stupid questions thread. I'll make sure to finish a bachelor's before i ask any stupid questions again.
>Frankly save us all some time and just go Google your question and the answer
I did before i posted the question.
also save you time? Why are you acting like you're obligated to answer anything.
If you feel your time is wasted it's because you chose to waste it, nobody can force you into wasting time least of all a faceless post on an imageboard.

[Anonymous No.15797771]

>>15797746
> i watched a single video
anon, are you serious? people gave you simple answers to the question which you didn't understand and refused to accept. what are you expecting us to do? give a lecture series on the mathematics of imaginary numbers?

[Anonymous No.15797777]

>>15797746
[math]a ^ b = e ^ { b \ln { a } }[/math]
if b = 1 then this reduces to [math] e ^ { \ln {a} } = a [/math] by definition of ln and e
if b = i then all bets are off

[Anonymous No.15797784]

>>15797771
>people gave you simple answers to the question
What simple answers? All I got were leading questions?
Can you tell me what simple answer didn't I accept?
I knew I must be wrong in my thinking somehow so i asked a stupid question in a stupid question thread, got people answering my question with questions then telling me i should have gotten a degree in mathematics before even asking the question
I didn't blame people for telling me I was wrong I knew I was wrong i just didn't know why.

[Anonymous No.15797799]

>>15797777
Thanks for an answer, I clearly don't know dick about anything really understand this but it does keep me curious.

[Anonymous No.15797802]

>>15797784
all these answers >>15797386, >>15797430, >>15797719. the fact you didn't understand what they were trying to tell you is glaring.

it's math. just because the question seems stupid or simple to ask that doesn't mean the correct answer is simple or easy. fermat's last theorem is a simple question ...

[Anonymous No.15797818]

I need someone to explain to me how to do polynomial problems in linear algebra, our professor is Danish so I don't understand a single thing that comes out of his mouth during lectures and the compendium he created for us is inadequate in every subject within the curriculum. I can't fully grasp how the kernel of P5 is P0, same for how the image of P5 is P4, we have exams in less than two weeks for fucks sakes...

If I were to gather a guess, with kernel we're finding what values will map onto the zero vector, I'm thinking that it's P0 because if P0 is a constant, we are mapping onto zero vector since the derivative of a constant is 0. As for the image, I believe from an educated guess that it is P4 because it's supposed to map all the outputs of the function, since F = p', and P5' = P4. How far off am I?

Do you think I have enough time to study from Gilbert Strang's Linear Algebra and it's applications these coming two weeks to get a beter grip on the subject? The compendium is so fucking ass, there's so much spelling mistakes, errors and just bad explanations. We've only been at it for >1.5 months so it's not far too much.

[Anonymous No.15797820]

How’s the post numbers system/designations throughout the site work? Like all the numbers in whatever this >>15797802 guy is talking about.

[Anonymous No.15797825]

>>15797604
It's a compendium the lecturer made for the course, it's shitty terrible trash, I didn't really read the answer they gave fully which is why it's as retarded as it is, I believe the correct answer is, or at least that this answer is less retarded: [math]\begin{pmatrix}
3 & 3 & 0\\
3 & 0 & 0\\
0 & 3 & 0
\end{pmatrix}[/math], what do you say? I'm thrown off by the change from v-basis to v-basis

[Anonymous No.15797843]

>>15797802
The first two i didn't dismiss i asked "why" in response, the third isn't an answer.
How in the world is that "not accepting them"?
I don't know why you're so hell-bent on pretending I'm belligerent.
Are you this offended i asked a question then asked another question in response to some of the answers?
Am i not supposed to ask questions in the stupid question thread?

[Anonymous No.15797866]

>>15797486
>>15797825
Your lecturer is correct.

[Anonymous No.15797875]

>>15797866
Are you sure? It doesn't seem to work for [math]\vec{v}_2[/math].

[Anonymous No.15797910]

>>15797875
Maybe it helps for you if you convert everything into the standard basis [math]B = (\vec e_1, \vec e_2, \vec e_3)[/math].

[eqn](F)_B^B = (\text{id})_B^{\underline v} (F)_{\underline v}^{\underline v} (\text{id})_{\underline v}^B = \begin{pmatrix} 1 & 1 & -1 \\ 1 & 0 & 1 \\ 0 & 1 & 1 \end{pmatrix} \begin{pmatrix} 3 & 0 & 0 \\ 0 & 3 & 0 \\ 0 & 0 & 0 \end{pmatrix} \begin{pmatrix} 1 & 1 & -1 \\ 1 & 0 & 1 \\ 0 & 1 & 1 \end{pmatrix}^{-1} = \begin{pmatrix} 2 & 1 & 1 \\ 1 & 2 & -1 \\ 1 & -1 & 2 \end{pmatrix}
[/eqn]
In this form it should be clear to see that it works
[eqn]
F(\vec v_2) = \begin{pmatrix} 2 & 1 & 1 \\ 1 & 2 & -1 \\ 1 & -1 & 2 \end{pmatrix} \begin{pmatrix} 2 \\ 0 \\ 2 \end{pmatrix} = \begin{pmatrix} 6 \\ 0 \\ 6 \end{pmatrix} = 2 \vec v_2

[/eqn]

[Anonymous No.15797957]

>>15797910
nice

[Anonymous No.15797998]

>>15797708
The left to right number line is left to right because of absence of any rotation. A right to left number line possess the action of flipping, while a down to up one possesses the action of rotating 90 degree. That is how the directions are defined.
Any complex number [math] r( \cos \theta + \mathfrak i \sin \theta) [/math] expresses a scaling by [math] r [/math] and a rotation by [math] \theta [/math]. So [math] \mathfrak i = \cos ( \pi/2) + \mathfrak i \sin ( \pi / 2 ) [/math] possesses no scaling but rotation by 90 degrees; hence, its square is simply the action of flipping i.e. [math] -1 [/math]. That is simply how the arithmetic is defined.

[Anonymous No.15798158]

From an evolutionary point of view, why does the attractiveness of the face plays such an important role in partner choice?
Apart from evident deformities or defects, it seems that it should be almost irrelevant. In males, it seems that things like height, strength or athleticism should be those selected by evolutionary pressure. Your offspring is no better off if you have a pretty face. In females, something like low waist-to-hip ratio, breast size, and again athleticism.
Yet my day to day experience contradicts this spectacularly. I see guys who are either short or fat get plenty of girls just because they have a very attractive face. I also see girls who are fat or whose bodies are not well proportionate get high-value guys just because they have a very attractive face.
Also, as a little experiment, to anyone who answers me, rate this faceless girl from 1 to 10.

[Anonymous No.15798206]

Find the straight line that intersects the point P(3, 1) and forms an angle of 45 degrees with
t : 2x + 3y - 1 = 0 . How do I solve this?

[Anonymous No.15798236]

>>15798158
8/10

+: Youthful skin, No irregularities, Conventionally attractive, Fashionably Fitted to body type.

-: AI design look (Looks a bit uncanny), Not within my the personal taste (Subjective).

[Anonymous No.15798242]

>>15798158
Probably because your view of evolution is incredibly narrow and defined by years of being a degenerate who spends their time on 4chan.

[Anonymous No.15798287]

>>15798242
>your view of evolution is incredibly narrow
Why would you make such remarks in a thread called STUPID question thread, without explaining how I'm wrong? Posting ITT is an admission of stupidity, there is no point telling me again.

>degenerate who spends their time on 4chan
A tall and strong male can defend the mother and the children from other humans or animals. Large hips are anatomically well suited for childbearing (and in fact there is a correlation between fertility and low WTH ratio, as well as breast size). Athleticism makes you a good hunter and gives you an advantage when escaping predators.
I don't see how thinking these things has anything to do with 4chan

[Anonymous No.15798297]

>>15798287
Probably because we're all the same species and even among our own species, homosapiens have the smallest variation in their genetics of any known higher animal, so because you've been comparing different ethnicities and nationalities of humans as if they were different species or animals, this has given a false impression and introduced a huge bias in your ability to consider the individual impacts that immeasurably small variations between different humans have for selective breeding, also the fact that you're basing this not ever the span of modern human but seemingly on a couple hundred or thousand years of our existence instead, because we literally had sex with neaderthals and found them attractive too, and to answer your question you would have to go back to a mammalian ancestor of upright humans, and this is why I said that your view was so narrow.

[Anonymous No.15798301]

>>15798287
It's 4chan that has made you think that is a normal thought process. You really think people hundreds of years ago were looking at statistical charts of hip to breast ratios to decide on who to marry? You're deluded.

[Anonymous No.15798344]

>>15798297
>so because you've been comparing different ethnicities and nationalities of humans as if they were different species or animals
What the fuck? I never did that.
By the way, I don't understand the rest of your post.

>>15798301
>You really think people hundreds of years ago were looking at statistical charts of hip to breast ratios to decide on who to marry?
No I don't, and I never said or implied I did. You don't seem to know how evolution works. Due to random mutations, there must have been males who where attracted to a high waist to hip ratio (WHR), males who where attracted to a low WHR, and males who did not care about WHR. Since females with a low WTH ratio produce more children and with a higher survival rate, the (mutated) genes of the males who preferred the low WHR survived and propagated more than the others (natural selection). And it was so that virtually any man today prefers a low WHT. No one looked at charts.

[Anonymous No.15798365]

how

[Anonymous No.15798368]

>>15798344
You're talking about something that happened before humans even existed, like females of the species having larger hips than males. Attraction today is mainly cultural and there wasn't the kind of diversification or insane phenotypical differences that you're implying for early modern humans.

[Anonymous No.15798448]

>>15798368
>You're talking about something that happened before humans even existed, like females of the species having larger hips than males.
Ok, and? I never said that the answer to my question must strictly involve humans.

>Attraction today is mainly cultural
Source? It seems to be the opposite.
>In 11 meta-analyses, the authors evaluate these contradictory claims, demonstrating that raters agree about who is and is not attractive, both within and across cultures;
https://psycnet.apa.org/doiLanding?doi=10.1037%2F0033-2909.126.3.390

[Anonymous No.15798459]

>>15798448
You are confusing evolutionary selection with sexual selection.

[Anonymous No.15798484]

>>15790245
I asked ChatGPT but its being retarded.
Basically I asked for all known sources of microchimerism in humans and after some prodding it came up with the following list:
>1) Bidirectional transfer of cells between mother and fetus during pregnancy
>2) Twin-to-twin transfer in utero
>3) Organ transplantation
>4) Blood transfusion
>5) An individual’s older sibling, twin sibling, or vanished twin, with the cells being received in utero
>6) Sexual intercourse
"Can microchimeric cells be tested for DNA and compare that DNA to specific individuals?"
it basically said yes
"So microchimeric cells can be tested for genetic relation to the individual they are found in, and if no genetic relation can be found, this excludes twins, siblings, or the mother as possible sources for the microchimeric cells?" and for it to revise the list to
>1) organ transplantation
>2) blood transfusion
>3) sexual intercourse
Then I asked if the medical history is known, and they never recieved a blood transfusion or organ transplantation, those two can be excluded from the list too?
>You are correct! If the medical history of the individual is known, and never received organ transplantation, and never received a blood transfusion, the only remaining possible source of microchimerism in humans is sexual intercourse .
>I hope this clears things up!
So I asked if a woman exibits microchimerism, her entire medical history is known and she never recieved a blood transfusion or organ transplantation and the cells exibit no genetic relation to the woman, can it be concluded that she's had sexual intercourse before?
And it just went retarded and told me about how virginity is a social construct, and the United Nations Human Rights, UN Women and the World Health Organization called for a global ban on virginity testing as it is a painful, humiliating and traumatic practice that constitutes violence against women

So, could you theoretically use microchimerism as a virginity test for women?

[Anonymous No.15798511]

>>15798365
Vertical force is [math]F_g=m\cdot g[/math]
Horizontal force is [math]F_{Z}=m\cdot \frac{v^2}{L}[/math]
resulting force is those two combined.
with [math]\theta[/math] being the angle between vertical force and the resulting force that is the addition of [math]F_g[/math] and [math]F_{Z}[/math]
That'd make [math]F_{g}[/math] the adjacent and [math]F_{Z}[/math] the opposite.
So [math]\tan\theta = \frac{F_{Z}}{F_{G}} = \frac{m \cdot g}{m \cdot \frac{v^2}{L}} = \frac{g \cdot L}{v^2}[/math]

Though I have to admit I'm retarded and it's been years since I've done shit like that, so keep in mind thats not nesseccarily correct, just what'd make sense to me.

[Anonymous No.15798515]

>>15798484
Why be worried about if you dont plan on having sex with a woman? Do you imagine the day when we enslave all women and you have the option of enforcing a microchimeric test on your potential bride? Otherwise what is the point? What is actually the point of what you're talking about and how is it different from people's DNA being different when they eat a certain food or catch a common cold? Do you even know what the fuck you're talking about? Virginity makes no sense, it's not a scientific concept. The body was made to have sex, and your fetish for genetic testing of human sex slaves could never be enforced unless you truly believe that the world inexplicalbly transforms into a fascist utopio for incels within your lifetime. it's delusion, you're fucking crazy man, i need to know your address, i need to fuck you, i need to rape the fuck out of you

[Anonymous No.15798516]

>>15798365
Vertical force is [math]Fg=m\cdot g[/math]

Horizontal force is [math]F_{Z}=m\cdot \frac{v^2}{L}[/math]

resulting force is those two combined.
with [math]\theta[/math] being the angle between vertical force and the resulting force that is the addition of [math]F_{G}[/math] and [math]F_{Z}[/math]

That'd make [math]F_{G}[/math] the adjacent and [math]F_{Z}[/math] the opposite.
So [math]\tan\theta=\frac{F_{Z}}{F_{g}} = \frac{m \cdot \fact{v^2}{L}}{m \cdot g} = \frac{v^2}{g \cdot L}[/math]

Though I have to admit I'm retarded and it's been years since I've done shit like that, so keep in mind thats not nesseccarily correct, just what'd make sense to me.

[Anonymous No.15798522]

>>15798515
It was in relation to some youtube comment war were people on one side were claiming that
>the existence of a Hymen is no indicator of virginity, as it can be destroyed through non sexual activities like riding a bike etc
while the other side argued:
>it may not be a flawless indicator, but its the best method we have. No hymen no diamond.
So I wanted to interject that there could be theoretically options to use genetic testing on microchimeric cells in a womans bloodstream, as well as her documented medical history to determine virginity in an individual, however I wasn't sure if this is actually possible and hence wanted to ask ChatGPT and now /sci/ if I'm talking shit or if this would actually be a viable method before posting.

[Anonymous No.15798524]

>>15798516
yeah that red part should be [math]\frac{m \cdot \frac{v^2}{L}}{m \cdot g}[/math]

[Anonymous No.15798528]

>>15798522
do something better with your time

[Anonymous No.15798533]

>>15798528
why? I like arguing with idiots on the internet, why else do you think I'm here?
BTW the context was a youtube video where some woman from a south east asia 3rd world country destroyed her hymen during a non sexual activity, and instead of telling anyone had a secret Hymenorrhaphy (hymen restoration), but there were medical complications which resulted in her family and fiance to find out who called off the wedding because they thought she cheated and wanted to hide that fact by doing a Hymenorrhaphy

[Anonymous No.15798534]

>>15798522
seriously bro, touch some grass.

[Anonymous No.15798536]

>>15798242
>>15798515
>>15798528
Lmao since when triggered roasties lurk sqt? Those were legitimate questions and you should GTFO

[Anonymous No.15798539]

>>15798536
I'm a woman. I'm a lady woman. Hee Hee. Tee Hee. Look at me Hoo Ha

[Anonymous No.15798544]

>>15798533
The solution to that wouldnt be genetic testing to prove that she was a virgin, it would be to overthrow the stupid shitty fucking government and eliminate that shitty backwards culture.

[Anonymous No.15798560]

Will technology ever reach a point where human minds can’t understand it anymore? I can barely understand some of the higher level stuff

[Anonymous No.15798563]

>>15798544
she's accused of cheating, sleeping with some random dude WHILE being engaged to her fiance, so she herself wants to prove her virginity and hence that she didnt cheat despite having her hymen destroyed, wouldn't genetic testing on possible microchimeric cells help her? (if that is even a viable method, maybe there are other methods how microchimerism in humans can occur that retardGPT forgot to mention, hence my asking here.)
Do you think cheating in relationships is okay?
Do you not believe in monogamic relationships at all and people should just engage in intercourse whenever and with whoever they want?
Aren't people allowed their own judgement if they want their relationship to be "exclusive" or not?

[Anonymous No.15798565]

>>15798560
We already fail to understand much of what is going on inside the largest and most complicated AI models.

[Anonymous No.15798568]

>>15798563
No, she's a victim of her culture, and if her country developed the technology to force women to be tested for virginity then it would only be abused and more women would be victimized. Use some critical thinking for fuck's sake.

[Anonymous No.15798569]

>>15798565
But how is technology exponentially growing if we barely understand it anymore?

[Anonymous No.15798572]

>>15798563
>Do you not believe in monogamic relationships at all and people should just engage in intercourse whenever and with whoever they want?
Why are only women the one's being tested and subjected to government inspections of their genitalia?

[Anonymous No.15798583]

>>15798572
>subjected to government inspections of their genitalia?
Yes, thats the entire point, that checking if the hymen is intact is not a viable method to determine virginity in woman, thats what started the argument I explained in >>15798522 >>15798533
So I wanted to find out if there are other non invasive and more accurate ways to test that in >>15798484 as a simple blood test with through venipuncture is enough to screen for existing microchimeric cells, and if found seperate them for genetic testing.

>>15798568
I do not understand, at what point is she victimized by her culture? She and her fiance have been engaged since youth, but suddenly they find her in a hospital after medical complications of a hymen reconstruction she underwent in secret without telling anyone, infidelity is the obvious conclusion, but she's adamant she didn't cheat and wants to proove that.

[Anonymous No.15798600]

>>15798583
One time I met a woman and we started dating and had sex and now we go on this website and laugh at people like you.

[Anonymous No.15798668]

>>15798459
You still haven't posted a source.

[Anonymous No.15798795]

>>15797866
>>15797910
Alright, that's good, thank you, I'll try to understand what's going on

[Anonymous No.15798817]

>>15798484
if you're under 20 you should focus on finding someone you love. you'll know if she's being reasonable & truthful about whether she's a virgin
if you're over 20 it's too late for you. it's over. you will never ever have sex if this is on your mind. you are withered
hope this helps

[Anonymous No.15798941]

Why was I cursed with such unrelenting idiocy?

[Anonymous No.15798964]

>>15791589
equal and opposite reactions.
F(a->b) = - F(b->a)
doesn't work out pretty if you rearrange F=ma. Again, gravity is a special case, and the fact that it is proportional to m is addressed by general relativity, which ends up stating F=ma is more fundamental anyways

[Anonymous No.15799001]

>>15798817
>>15798515
I'm not asking for social advice, I want to ask people who are educated in Biology and/or Medicine and have knowledge on microchimerism in humans if the existance of microchimeric cells and their genetic relation to the individual could be used to determine wheither an individual has had sexual intercourse before, as the fact that microchimerism in itself exists and can be caused by something as mundane as sexual intercourse is fascinating.

You do not know anything about me, I could be a female, a male homosexual, or asexual of either gender, and this topic doesn't personally affect me in any way besides the want for knowledge, and you assuming characteristics about my gender, age, or personality based on a genuine scientific interest in microchimerism is frankly quite rude.

[Anonymous No.15799056]

>>15799001
The answer is no. Now fuck off, you're an annoying cunt and probably an incel too.

[Anonymous No.15799072]

>>15799056
>The answer is no
well, can you elaborate what mechanism prevents this from being an option,
Are there other sources of microchimerism that weren't mentioned that can't as easily be accounted for?
From what I've been able to research so far on my own not all individuals who were subjected to one or multiple known sources that may cause microchimerism in humans do actually display microchimeric cells in them, as the immune system of some individuals have different reactions ot microchimeric cells and may purge them from the body, while exposure to enviromental toxins may reduce the immune response and increase the chance and prevalence of microchimerism occuring.


If you all really need to know my personal characteristics before you honestly decide to engage with my question, I happen to be an autistic female asexual in my early 20's and have no personal or political "agenda" or ulterior motive in this topic beyond genuine curiosity that you seem to ascribe me to have.
And to be honest I am unsure if or why my question pertaining to medicine and biology seems to have caused offense in any way, as I tried my best to be respectful even when you and others have acted rude and dismissive towards me based on wrong assumptions about my intentions or personal characteristics.
Like, people in this thread have not just insulted me, but even threatened violence upon me for asking what I percieve to be a relatively normal and harmless question that I believe is on topic for this board and thread, and I seriously do not understand why.
I hate to play the "please be patient, I have autism"-card, but I may lack the social awareness and genuinely do not understand why everyone is so rude towards me for asking a simple biological/medical question that came to me when reading a discussion on youtube.

[Anonymous No.15799127]

>>15799072

[Anonymous No.15799138]

>>15798242
>>15798297
>>15798301
>>15798515
>>15798528
>>15798544
>>15798600
>>15799056
Holy fucking shit you're a fucking low-life. You have *not* answered anything and just forcedly and needlessly brought in politics and personal attacks to anons who asked a well articulated *scientific* question.
Also
>do something better with your time
Has to be the saddest post I've ever seen on a science board. Historically, all scientific advancements came from people pursuing their curiosity freely, and those people were almost invariably seen as "wasting time" by non-scientists of the time. It's unbelievable that people like you are on this board.

[Anonymous No.15799234]

I'm a tourist from /g/, but why do some people on /sci/ say maths is pozzed?

I mean, maths/physics is about as hard as hard sciences get, right? Something about academia and politics?

[Anonymous No.15799267]

>>15799234
Because science uses unbiased evidence, facts and logic to reach a conclusion. /pol/ doesn't.

[Anonymous No.15799285]

>>15799267
Now I'm even more confused, I don't even go on /pol/. Are you insinuating that those people are /pol/? I didn't even realize /sci/ and /pol/ even intermingled that much.

[Anonymous No.15799296]

I studied that a capacitor works by creating total induction of an electric charge from a conductor to another conductor (like two parallel planes, a sphere inside a hollow sphere, etc)
In the real capacitors like the pic I posted what shape do the conductors have? I don't understand how they really are on the inside and can't find any source that explains it that isn't a picture of two parallel planes

[Anonymous No.15799298]

>>15799234
Reproducability crisis is a widely acknowledged problem, with multiple claimed contributing causes, one being pozzing. A few recurring complaints about the state of physics research, no pozzing other than niel degrasse and bill nye being clowns. I haven't heard anything about math being pozzed.

[Anonymous No.15799302]

>>15799285
It's a general term u muppet, because we all know there is a strong overlap between the people you are talking about and those on a certain board here who then shitpost across the whole site. People who have a rigid viewpoint already and then cherry pick evidence to fit their world view.

[Anonymous No.15799341]

I'm writing an assignment paper, but most of the sentences keep getting tagged as AI ('56% chance it's AI'). I keep trying to dumb down the grammar and vernacular, but it keeps giving me the same output unless I completely butcher the structure of the paragraph.

What do I do? I'm paranoid about instructors haphazardly using GPT detectors and accusing me of academic offense.

[Anonymous No.15799353]

Help for 2 and 3 would be much appreciated

[Anonymous No.15799376]

>>15799341
Stop being paranoid. Just do the work and stop being a dumb fuck.

[Anonymous No.15799392]

>>15799376
I fixed it. I have a lot of run-on sentences now, but I doubt my lab instructor will care..

[Anonymous No.15799412]

>>15799353
the chapter in your book should explain it pretty well, if not just google trig unit circle

[Anonymous No.15799428]

>>15799296
ceramic capacitors are two circular metal discs.
electrolytic capacitors are two sheets that are rolled together into a fat cylinder.
>>15799353
you need help for question 1 too. if the question asked you to convert to radians, your answer should be in radians, no?
question two is either plugging cos^-1(1/2) or sin^-1(sqrt(3)/2) into a calculator, or just memorizing that those are both 60 degrees.
question three should be obvious from the diagram and the definition of sin.

[Anonymous No.15799434]

>>15799428
Lol, I was second guessing myself saying "there's no way they made it that easy, I'll ask for help" turns out they did make it that easy. Thanks for the help, anon

PS: the radians is a typo

[Anonymous No.15799440]

>>15799434
np, anon.
also, did you write down that the hypotenuse is 2? cause its not, its 1, thats a unit circle.

[Anonymous No.15799484]

what does it mean for a differential equation to be homogeneous
I know that the definition for a first order is when it has the expression y/x, and for higher orders when it's in the form of ay'' + by' + cy = 0 or for however many derivatives there are, but what does "homogeneous" actually signify

[Anonymous No.15799503]

>>15799484
the terminology is rooted in the fact that such an equation is homogeneous with respect to the function and its derivatives. which is a fancy way of saying that if you multiply the inputs by some value, the output will be multiplied by a power of that value (very easy if the thing solves to 0 anyway).
practically speaking, what it means is that if you find a solution to the equation, then any multiple of that solution will also be a solution

[Anonymous No.15799506]

What if we reached the height of human discoveries? All that is left for humans is to collect meaningless data that can never be used for anything
What if this is the peak?

[Anonymous No.15799540]

>>15799484
consider the equation [math]x^2-xy-y^2=0[/math]. notice that every term is of degree 2 (zero is a wildcard, its every degree). because of that, you can multiply a solution by some scalar and get another solution. for example, if (a,b) is a solution, then (4a,4b) is also a solution. this is because every term gets a new factor of [math]4^2=16[/math] which can simply be factored out and discarded. its easy to see in a differential equation how the same principle applies; just consider the degree of every term. if theyre all the same, then the equation is homogeneous.
bonus: if we multiply by something clever, like [math]\frac{1}{y}[/math], then our equation becomes [math]\left( \frac{x}{y} \right) ^2-\frac{x}{y}-1=0[/math]. since [math]\frac{x}{y}[/math] is just some fraction, we'll rename it to [math]z[/math], and our equation becomes [math]z^2-z-1=0[/math]. so we took an equation in two variables and changed it to only 1 variable. the only problem is when y=0, but its easy to see (at least for this example) that x=0 is the corresponding solution. neat, right?

[Anonymous No.15799554]

lets take a random [math]x \in \bigcup_{n\in\mathbb{N}}^{}[-n,1/n)[/math]
that means [math]\exists n \in \mathbb{N}: -n \leq x \ leq 1/n [math]
we know that n >=1 and by the conditions we are given x>=-n and x<1/n. We know that -n goes to -infinity, therefore can say....

because 1/n<=1, for all natural numbers, then we know that x<1, for all natural numbers therefore the union is equal to (-inf;1)

can anyone fix my proof and write how i can prove that x being >=-n means that the set goes to -inf? also if I have an intersection can i also use the \exists n that belongs to N: .... the same way?

[Anonymous No.15799556]

[math]\exists n \in \mathbb{N}:. -n \leq x \leq 1/n [/math].

[Anonymous No.15799570]

>>15798941
You were not. Please be kind towards yourself. You can only grow in an environment of profound self-forgiveness and love.

[Anonymous No.15799609]

how do I do this?
Given the sets A = {2k + 6 : k ∈ Z} and B = {4l - 8 : l ∈ Z}.
a) Is A ⊂ B? Justify.
b) Is B ⊂ A? Justify

[Anonymous No.15799616]

>>15799609
For a) find an element in A that is not in B and for b) rewrite 4l - 8 into the form 2(...)+6 where (...) is an integer.

[Anonymous No.15799632]

>>15790245
Scientifically speaking, do pallas cats like sritches?

[Anonymous No.15799650]

>>15799138
You will never be a scientist.

[Anonymous No.15799702]

is there any data which justifies if taking notes on paper, touch pad w/ stylus or with a keyboard via LaTeX or some other software yields better knowledge retention than the other?

[Anonymous No.15799714]

>>15799609
A ⊂ B iff x in A and x in B.
are there values in set A which also are values in set B?

[Anonymous No.15799823]

ignore this, im reposting some posts from the archive because warosu doesnt have mathjax

Let's start with an easy example: consider the integral
[eqn]\int_1^a \frac{\mathrm{d}x}{\sqrt{1-x^2}}. [/eqn]
With some work, one shows that the differential [math]\omega=\mathrm{d}x/\sqrt{1-x^2} [/math] is invariant under a rotation of the circle. So, after a change of variable, we get
[eqn]\int_1^a \frac{\mathrm{d}x}{\sqrt{1-x^2}}=\int_b^{c} \frac{\mathrm{d}x}{\sqrt{1-x^2}}, [/eqn]
with [math]c=ab-\sqrt{(1-a^2)(1-b^2)} [/math].

What is happening here? We have a plane curve [math]C:y^2=g(x) [/math], [math]g(x)=1-x^2 [/math], which also admits a group law (given by rotation) we have found a differential [math]\omega=\frac{\mathrm{d}x}{y}[/math] which is invariant under translation for this group law, and so we can compute the integral
[eqn]\int_{O\to P} \frac{\mathrm{d}x}{y}=\int_{Q\to P+Q} \frac{\mathrm{d}x}{y} [/eqn]
by making a change of variable. Here [math]O=(1,0) [/math] is the identity of the group law, don't confuse it with the origin of the plane. But here this fact is not playing a crucial role, we could have started from any other given point [math]P_0 [/math]. Also, the path [math]O\to P [/math] that we've chosen is not important, but we should be coherent about it: [math]Q\to P+Q [/math] should we that same path, traslated via [math]Q [/math]. Now we're on a circle so there aren't many paths to choose (you could go either clockwise or anti-clockwise, though), but note that all this also works when considering the *complex* solutions to that equation. Now it's topologically a surface, and so we have many different ways of going from [math]O [/math] to [math]P [/math]

[Anonymous No.15799827]

>>15799823
Likewise, we can start from [math]C:y^2=g(x) [/math], [math]g(x)=(1-x^2)(1-k^2x^2) [/math], [math]\omega=\frac{\mathrm{d}x}{y} [/math], and try to compute the integral
[eqn]\int_{O\to P}\omega, [/eqn]
where [math]O=(1,0) [/math]. Again, we find that [math]C [/math] admits a group law (hopefully? I couldn't find anything online), with something like [math]P+Q=(\frac{x(P)y(Q)+x(Q)y(P)}{\sqrt{1-k^2x(P)^2x(Q)^2}},\sqrt{g(x(P+Q)}) [/math] (but I really don't like the fact that some square roots appear, since the whole reason why we introduced [math]y [/math], and considered a plane curve, was so that we could make coherent choices of square roots by having [math]y [/math] move continuously). Anyway, we also find that [math]\omega [/math] is invariant under translation for this group law (I didn't actually check this), so we can again make the change of variable
[eqn]\int_{O\to P}\omega=\int_{Q\to P+Q}\omega, [/eqn]
and so we get the sought-after formula:
[eqn]\int_{O\to P}\omega+\int_{O\to Q}\omega=\int_{Q\to P+Q}\omega+\int_{O\to Q}\omega=\int_{O\to P+Q}\omega, [/eqn]
where we compose the paths we're taken as our choice for [math]O\to P+Q [/math].

One works analogously when [math]E:y^2=g(x) [/math], where [math]g(x)=x^3-px-q [/math] is a cubic with three distinct (complex) roots. Here the group law is given by the chord and tangent method (note that we have to also consider the point at infinity, to make everything work), and the fact that [math]\omega [/math] is invariant can be checked without much of a computation, since in this case one can prove that the space of holomorphic differentials on this curve is 1-dimensional; so, if we call [math]t_Q [/math] the translation by [math]Q [/math], then we must have [math]t_Q^\ast\omega=c(Q)\omega [/math], for some [math]c(Q)\in\mathbb{C} [/math] depending algebraically on [math]Q [/math]. So, we have a morphism [math]E\to \mathbb{C} [/math], which must be constant. Since [math]c(O)=1, [/math] we conclude.

[Anonymous No.15800095]

>>15799650
I don't need to be a scientist to call out blatant cunt-behaviour

[Anonymous No.15800103]

>>15790245
why is the sci sticky link dead? it says
>Site disabled
>The Google Account of a site owner has been disabled because of a perceived violation of the Terms of Service. The site owner needs to restore their Google Account before this site can be viewed. Learn more
https://sites.google.com/site/scienceandmathguide/
I'm still able to find it on archive.org but I'm concerned about the loss of knowledge here, is there a replacement in the works?

[Anonymous No.15800125]

does it sound reasonable to through precalc, calc, linear algebra, and baby rudin in a few months?
considering all I do is sit at home and code monotonous shit for work

[Anonymous No.15800138]

How would (you) test the question of whether fetishes are taught vs inherited? My thought was maybe looking at cross cultural fetishes: if fetishes are inherited then we would imagine a roughly equal % of populations A and B are into vore, whereas if they're taught then the populations would differ.

[Anonymous No.15800160]

Okay, all the stuff with hypersonic speech jamming and social engineering and some of the model manipulation tools for generative AIs is making me think about brains differently.

Other than shutting off speech, in what ways can minds, or the greater nervous system, be affected by energy, drugs, sensory conditions, or whatever else that actually bypass the psyche?
I don't mean general broad things like complete sensory deprivation or dropping LSD or shrooms or smoking DMT or the placebo effect, I mean specific things like:
>poke this part of your palm to relieve nausea
>hold your breath while drinking water through a paper towel to inhibit hiccups
>alternate between smacking someone's left and right ears with cupped hands to knock them out from the pressure differential (old bartender trick, probably dangerous)
>the house meme where the mirror box relieves phantom pain in amputee
>hit in solar plexus, hard to breathe even though not actually paralyzed
What are some bugs or exploits for the human body?
Can you make someone functionally blind for a period of time without neural or ocular damage or any sort of "hypnosis" or suggestion?
Loss of sense of balance, ability to comprehend language, continence, ability to properly reconstruct visual information, are there specific hallucinations you can reliably create with some odd setup or factor?
I promise I'm not a supervillain I'm just curious.

[Anonymous No.15800162]

Am I retarded? If m == 1 (mod p), won't it always be the case that p does not divide m?

[Anonymous No.15800163]

>>15800138
A lot of things which have reemerged as modern fetishes were independently discovered as being common in various perverse and cruel tribal societies, and probably just as many started or became more common in "civilized" parts from tales about tribal behaviors getting back to people.
It seems like today a lot or most people get it from repetitive exposure, often incidental, from porn. Previous to that it was probably a lot of incidental exposure to things in childhood or youth helped out by paucity of other sexual input, thus making it more of a focus. Too much or too little input both seem to skew the resulting "data sets" inside the neural networks, either way.

My fetish, on the other hand, is very based and natural and Good People would share it and agree with me and the Real Human Nature includes it as part of natural sexuality and it's just suppressed and misunderstood by Perverted Hypocrites, thus it Is Not Weird Or Pedophilic To Try To Force Kids To Learn About It.
(seriously what the fuck is with public schools)

[Anonymous No.15800187]

>>15800103
anyone? what are we to do without the sticky! this is our burning Library of Alexandria. any posts in the archive to read into about this

[Anonymous No.15800198]

what is it about bicycles that can't be solved?

[Anonymous No.15800201]

>>15800198
Why they so often turn people into insufferable cunts even though by all indications they should mellow them out and make them cooler.

[Anonymous No.15800208]

Does the many worlds interpretation of quantum mechanics need to be untestable by its definition, or is it possible to have theories where influence from the other worlds is detectable?

[Anonymous No.15800212]

>>15800187
convince my boss to buy fiber internet and ill host the site.
>>15800208
>is it possible to have theories where influence from the other worlds is detectable?
thats the whole point. when a photon goes through the right slit, it interferes with the parallel universe version of itself that went through the right slit.

[Anonymous No.15800216]

>>15800212
I meant the interference keeps having an influence even after it has passed through the slit and hit the detector, just that the influence has to be detected through a more convoluted means past that point.

[Anonymous No.15800224]

>>15800208
It's the definition of the words anon. An interpretation is an explanation of what a theory means, it gives a physical explanation of the mathematics of a theory.They are not testable because they make no new predictions, they are not new theories.

Many Worlds is a strange hybrid. It was created to try and explain various conceptual problems with the theory of quantum mechanics. It can be called a theory because it has its own equivalent to the Schroedinger Equation, the mathematics of how to perform quantum calculations is different to standard theory. However it is still called an interpretation because all the answers it gives are identical. It makes no new predictions, it is not testable (at least no one has come up with a working test for it so far).

[Anonymous No.15800249]

>>15800224
Has anybody tried creating as much world divergence as possible to see if anything strange happens?

[Anonymous No.15800260]

>>15800249
We see nothing strange. A world divergence is simply a particle interaction. They happen all the time in unfathomable numbers.

[Anonymous No.15800263]

>>15800260
But the difference between worlds formed by everyday particle interactions is very small, in spite of how numerous they are. The state of a single particle doesn't make the difference between somebody's life going in two completely different directions.

[Anonymous No.15800266]

this is a bit of an unusual one but:
how do you call it when someone puts you in a position where you can't defend yourself because they make it sound like you try to rationalize everything? is this one of the fallacies?

[Anonymous No.15800268]

>>15800263
Again, we have no test to see these new worlds (if they even exist).

[Anonymous No.15800274]

>>15799506
as far as human's quest for achievement there is no peak, you could say theres technological walls that require breakthroughs and I do think we might be at one of those now, space travel is one of those walls, and so is advanced medicine

[Anonymous No.15800575]

>>15800266
double bind may be what you're looking for

[Anonymous No.15800860]

>>15800198
How they stay up and if it is gyroscopic procession.

[Anonymous No.15800922]

If there is a limit going towards some value [math]a^2[/math] such that [math]a>0[/math] is in the argument's denominator [math]\sqrt{x}+a[/math], why do we ignore the negative root of [math]a^2[/math] here and just proceed to let [math]x=a^2[/math] and get rid of the limit?

[Anonymous No.15800935]

>>15800922
You answered your own question. The limit is going to [math]a^2[/math], not [math]\pm \ a[/math]. Also remember that [math]\sqrt{x^2} = |x|[/math].

[Anonymous No.15800983]

>>15800935
So it is just a convention in this case... ? We just decide to ignore the negative root.

[Anonymous No.15800987]

>>15800983
I'm not sure what you mean by convention. It's the definition of a square root, it returns one value, the principal root.

[Anonymous No.15801103]

how do I prove that if 2 l 7g, then 2 l g?

[Anonymous No.15801108]

>>15801103
7g is even, but since 7 is odd then g cannot also be odd, it has to be even.

[Anonymous No.15801110]

Given the sets A = {2k + 6 : k ∈ Z} and B = {4l - 8 : l ∈ Z}.
ok so b= 2(2l-7)+6, a=2k+6, how do I prove from this that b is a subset of a? I know that 2k contains all even numbers, and 2(2l-7) contains even numbers, but not all, but how do I prove this?

[Anonymous No.15801117]

>>15801110
Set k=2l-7.
That's it. That's literally all that there is to it.

[Anonymous No.15801158]

what is "5" in chemistry for prefixes, where there are 5 molecules
Like on explosions&fire YouTube channel

[Anonymous No.15801259]

>>15800987
>it returns one value, the principal root.
Well, both [math]x[/math] and [math]-x[/math] when squared give the same quantity, and sometimes when doing algebraic problems (from a workbook) I know it's an error to not include both roots in my solution. So I don't understand why when doing limits we disregard the negative root.

[Anonymous No.15801267]

>>15801110
how tho? k is all integers if we set it to 2l-7 where l is an integer k isn't all integers anymore

[Anonymous No.15801269]

>>15801259
It depends on how the question is written. Asking what is [math]y[/math] when [math]y^2 = 9[/math] or [math]y = \sqrt{9}[/math], they do not have the same answer.

[Anonymous No.15801279]

>>15801267
Irrelevant.
We want to show that B is a subset of A.
If we write k=2l-7, then we can write any element in B in the form 2k+6, as you have demonstrated.
So any element in B can be written in a form that would place it in A. Thus every element in B is also in A, and so B is a subset of A.

[Anonymous No.15801328]

>>15790245
International brother, I need your help. 0.7x0.127 copper wire with a thermal outer diameter of 0.7. When the extrusion amount is 8. Why does it keep disconnecting from the connector? Why? Why? Why? I've smoked 4 cigarettes. I really want to jump from the stairs. I can't stand it

from
>>>/int/188555958

[Anonymous No.15801337]

>>15801328
>crosslinking the int thread so i can see what country youre from and make my decision of whether or not to provide help based on my affinity for your nationality
you played yourself, wang.

[Anonymous No.15801360]

Is this solution correct?
take any x∈⋂n∈N(-1/n,n]st∃n∈N:-1/n<x<=n

We know that n>=1, so x<=1 for every n
we also know that -1/n<=0, for every n
so we get that 0<=x<=1
or x\in[0,1].

[Anonymous No.15801394]

>>15801269
Wdym? In both cases [math]y=\pm 3[/math].

[Anonymous No.15801634]

>>15801394
You are wrong.
[eqn]y^2 = 9 \implies y = \pm\ 3 \\ y = \sqrt{9} \implies y = 3[/eqn]

[Anonymous No.15801802]

bros, I need a good /sci/ approved dynamical systems textbook. Something rigorous, preferably. I already have Strogatz, but it is very introductory and easy.

[Anonymous No.15801858]

Why does Shaldon Axler hate determinants, in simple terms?

[Anonymous No.15801949]

What is the best starting point data if I want to calculate the mean times an average, healthy adult female in her 20s to 30s urinates per day, along with the approximate cumulative urinations per year?

This is for very scientific and diverse purposes I promise.

[Anonymous No.15802095]

What's the point of geometry when you could just measure everything with a ruler?

[Anonymous No.15802177]

>>15791292
You should probably look up all the technical terms you don't know, then formulate a precise question and ask again.

[Anonymous No.15802186]

>>15801949
Find the average amount of liquids consumed per day, and the average bladder capacity before urination. Seems like both should be somewhat well studied.

[Anonymous No.15802201]

>>15802186
But what about perspiration and exhalation?
(and all I find is very approximate tentative ranges, no one seems to study this)

[Anonymous No.15802277]

>>15801634
Do we ever use [math]\sqrt{x^2}=\pm x[/math] in math?

For example, when solving the [math]y^2=9[/math] I would go:

[eqn]
y^2=9 \\
\sqrt{y^2}=\sqrt{9} \\
y=\pm 3
[/eqn]

So, the square root must return [math]\pm x[/math] generally.

[Anonymous No.15802281]

>>15801634
brainlet here. isn't -3 x -3 = 9?

[Anonymous No.15802295]

Noob question but how do you add periodic angles in trigonometry? I know that I just add the angles but what do I do with the period [math]nk\pi[/math]?

[Anonymous No.15802297]

>>15802281
it is

[Anonymous No.15802304]

>>15802277
> Do we ever use [math]\sqrt{x^2}=\pm x[/math] in math?
No. Even if [math]x[/math] is negative [math]x^2[/math] will always be positive so taking the square root will never be negative. Which is why [math]\sqrt{x^2} = |x|[/math].

> So, the square root must return [math]\pm x[/math] generally.
Wrong. I think you need to go back to your textbooks and read what the square root function actually does.

> when solving ... I would go
You got the correct answer but more by luck than knowing what you are doing.

[math]\begin{align}
y^2 &= 9 \\ \sqrt{y^2} &= \sqrt{9} \\ |y| &= 3 \\ \pm\ y &= 3 \\ y &= \pm\ 3
\end{align}[/math]

>>15802281
Yes, but I hope I answered the rest in this post.

[Anonymous No.15802341]

This question asks: For the pumping lemma, L = { uu | u∈{a,b}* }, if in response to the given n we play w=(a^n a^n), the opponent has a chance to win. How?

[Anonymous No.15802368]

>>15802304
Thanks, I think I get it now. I thought about the square root in a wrong way my whole life.

[Anonymous No.15802385]

>>15802368
It's a mistake lots of people make because in the questions we are given when we first learn about square roots it doesn't make a difference and typically [math]x \ge 0[/math].

[Anonymous No.15802409]

>>15801858
Most graduate linear algebra textbooks avoid determinant. They don't extend to infinite dimensional spaces and proofs without using determinant are much more enlightening.

[Anonymous No.15802448]

>>15802277
Ignore all principal square root faggotry

It's an arbitrary crowbar of a """function""" forcing the squareroot to be analytical (it's not, and will never be) for no logical purpose
Mathfags use these bullshit hack functions then wonder why their calculations never work

>So, the square root must return ±x generally.
Always, yes

[Anonymous No.15802733]

if 3 l 5g, how do I prove that 3 l g?

[Anonymous No.15802736]

>>15802733
Euclid's lemma

[Anonymous No.15802745]

>>15802736
I get g=3bq/5, is bq/5 an integer?

[Anonymous No.15802770]

>>15802745
You don't have to show anything. Euclid's lemma is proof enough since [math]3 \not| 5[/math].

[Anonymous No.15802812]

>>15802770
Ok, is this correct too?
If 3 l 5g that means 3c=5g, that means 5g must contain a factor of 3 and since 3 doesn't divide 5 that means 3 must be a factor of g.

[Anonymous No.15802813]

>>15802812
thats fine but you dont need the 3c=5g part, you can just say "if 3 l 5g then 5g has a factor of 3", and even that is pretty verbose.

[Anonymous No.15802828]

>>15790245
Why are women allowed in grad school? Why are women allowed to TA? Women are so fucking dumb it is impossible for the female brain to account for any novel complex thought pattern that reliably translates into concrete research. I ask again: why are women allowed in grad school?

[Anonymous No.15802846]

>>15802828
Let me guess, you didn't get into grad school.

[Anonymous No.15802937]

Without using a calculator, find the exact value of the expression:
12sec(240∘)/2sin(150∘)
.

[Anonymous No.15802949]

If I put some potassium carbonate in my wine or beer for example in order to spice it up a bit.
Is it safe to consume a solution like this?
why?
why not?
https://www.youtube.com/watch?v=1SS3-D-Aqr4

[Anonymous No.15802954]

>>15802937
150 degrees is 5pi/6, and 240 degrees is 4pi/3. sin(5pi/6) is 1/2, and sec(4pi/3) is -2.

[Anonymous No.15803002]

I don't get what they're saying here
how is y(t) not zero when cost=0??? I must not be reading it correctly.

[Anonymous No.15803004]

Diffgeo homework is asking for a local isometry between the catenoid and the helicoid
I worked out the metrics and apparently the catenoid is a conformal transformation of the plane, while the helicoid isn't
But that would make finding a local isometry impossible, right? Where am I going wrong?

[Anonymous No.15803006]

>>15803002
>cost=0
big oof

[Anonymous No.15803021]

>>15803006
I don't udnerstand what you mean by this. Please be more direct.

[Anonymous No.15803023]

>>15803021
yea my bad bro i didnt really read your post.
>>15803002
its clear from the non-factored expression that even when cos(t) = 0, y is not zero. as a result, the cos(t) of the factored version doesnt contribute any zeros the way it normally would when you multiply things by zero. the reason is because when cos(t) = 0, tan(t) = infinity, so youre multiplying zero by infinity which might not be zero (the real reason this is happening is because you factored cos(t) out even though its sometimes zero, and youre not allowed to factor out zero like that when it requires you to divide by zero).

[Anonymous No.15803027]

>>15803023
okay i understand

[Anonymous No.15803050]

I'm a bit of an ultra baka and I'm delving into the specifics of hydroponic agriculture, but I never had a proper education on the physics of light. Could anybody point me in the direction of a resource to learn about measurements, tools, and methods for measuring light emissions? I'm really just trying to get to the point that I can measure a light source and evaluate its true "effective" emission for plants.

[Anonymous No.15803340]

If I wanted to learn about how to design my own guns, would I just have to go through the 4chan science MechE(with the prereq math of course) and Cooper's book on explosives engineering, or is there some more specialized works I should go through? How do I not get myself killed.
Before you ask, yes this is TF2 related.

[Anonymous No.15803409]

>>15803340
i dont think you even have to do all that, just study a bunch of guns, theyre all kind of the same.

[Anonymous No.15803410]

>>15803023
nta but i'm at the same place in my ODE class. Is there a reason they didn't just do
y(x) = 0 = Asin(x) + Bcos(x)
Asin(x) = -Bcos(x)
tan(x) = -B/A

[Anonymous No.15803421]

>>15803410
i dont think theres a specific reason.

[Anonymous No.15803453]

If we know that A is a deformation retract of X and B is not, can we conclude that A and B are not homotopy equivalent?

[Anonymous No.15803476]

should 0 be treated with the same care as infinity? god damn indeterminate forms

[Anonymous No.15803493]

>>15803476
Yes.

[Anonymous No.15803538]

>>15800138
>>15800163
are there any interesting studies on fetishes from before television

[Anonymous No.15803704]

>>15802846
It sounds more like they did get into grad school and he has to deal with them on a regular basis

[Anonymous No.15803706]

What's a good organic chmistry textbook, I need to reaquaint myself with the basics.

[Anonymous No.15803967]

new thread

>>15803735
>>15803735

[Anonymous No.15804480]

I don't know where I'm going wrong. The solution is [math]1/24[/math] but I'm getting [math]1/8[/math].
[eqn]
\lim_{x \to 8} \frac{2\sqrt[3]{x}-\sqrt{x+8}}{x-8} \\
= \lim_{x \to 8} \frac{4\sqrt[3]{x^2}-x-8}{(x-8)(2\sqrt[3]{x}+\sqrt{x+8})} \\
= \lim_{x \to 8} \frac{(\sqrt[3]{x}-2)(\sqrt[3]{x^2}+2\sqrt[3]{x}+4)}{(x-8)(2\sqrt[3]{x}+\sqrt{x+8})} \\
= \lim_{x \to 8} \frac{1}{2\sqrt[3]{x}+\sqrt{x+8}} \\
= 1/8
[/eqn]
Where's the mistake?