/sqt/ - Stupid Questions Thread

[Anonymous No.9316173]

tfw eternal brainlet

[Anonymous No.9316179]

>>9307840
previous thread

[Anonymous No.9316199]

Is there a name for when you are periodically extremely agressive (verbally) towards as many people as you can get to? It's bothering me and it's probably affecting me negatively.

Maybe once a day there will be a few hours where I'm in that state.

[Anonymous No.9316201]

Is it evolutionarily better to have a massive dick like Danny D or a small dick? If so, why?

[Anonymous No.9316206]

>>9316199
it's called being an abusive fuck

[Anonymous No.9316236]

i got Ni and NH3 in a pot, if i pour some NaOH what will happen?

[Anonymous No.9316242]

>>9316201
I didn't know Danny DeVito had a massive dick.

[Anonymous No.9316245]

>>9316201
There's an evolutionary benefit towards a long penis because it deposits sperm closer to the uterus, which means you can beat out the guy immediately before or after you.

[Anonymous No.9316258]

>>9316206
at least I'm not useless, unlike you.

[Anonymous No.9316264]

How can I show a cubic will have one real root, and two complex roots if all it's coefficients are negative?

[Anonymous No.9316276]

>>9316245
>the virgin horse-cock
>the chad pearly penile papules

[Anonymous No.9316287]

>>9316264
https://en.wikipedia.org/wiki/Descartes%27_rule_of_signs

[Anonymous No.9316301]

>>9316264
As the intellectual Donald Trump would say, WRONG

y=-x^3-5x^2-5x-1

[Anonymous No.9316304]

How does gravity explain helium balloons? We all know helium rises because it's lighter than air, but how can it be lighter than gravity? What force is pushing the balloon "up"?

[Anonymous No.9316306]

Okay, so consider the operator [math]\frac{d^2}{dx^2} + 1[/math]. I'm supposed to find its Green function satisfying the conditions 0 at 0 and derivative wrt [math]x[/math] 0 at 1. My attempt was to set [math]G(x, y) = \alpha_1\sin x + \beta_1\cos x[/math], when [math]x<y[/math], and [math]G(x, y) = \alpha_2\sin x + \beta_2\cos x[/math] when [math]x > y[/math]. I can, probably, assume 0 and 1 are the boundaries, since those are what are given, so [math]y \neq x \Rightarrow G(0, y) = \beta_1 = 0[/math], and [math]x \neq y \Rightarrow \frac{\partial }{\partial x}G(1, y) = \alpha_2\cos 1 - \beta_2\sin 1 = 0 \Leftrightarrow \alpha_2 = \beta_2 \tan 1[/math]. If I demand this function is continuous when [math]x=y[/math], then [math]\alpha_1 \sin y = \beta_2\tan 1 \sin y + \beta_2 \cos y \Leftrightarrow \alpha_1 = \beta_2 (\tan 1 + \frac{1}{\tan y})[/math]. Can I take this further, or is this the bitter end?

[Anonymous No.9316308]

>>9316304
Gravity is pushing nitrogen and oxygen molecules down harder than it pushes down helium molecules.

The nitrogen and oxygen displace the helium, pushing it up.

TL;DR Balloons actually float due to gravity.

[Anonymous No.9316332]

>>9316308

Why does gravity push down less on helium?

[Anonymous No.9316339]

>>9316332
Because helium atoms have less protons and neutrons, and hence less mass.

In general, the higher something is on the periodic table, the less dense it will be.

[Anonymous No.9316346]

>>9316308
Wrong! If you picture a Helium balloon, that ballon is surrounded by heavier air. Including air on top of it. If the air on top of it is being pulled down, how come this does not push down the balloon?

[Anonymous No.9316351]

>>9316304

Buoyant forces. The same force that makes bubbles rise up when underwater.

[Anonymous No.9316365]

>>9316346
gravity pressure gradient.

that's all.

the higher you go the lower the atmospheric pressure is.

this means that if you follow the boundary of the balloon from bottom to top, the air surrounding the balloon will have lower and lower pressure on the balloon, resulting in a net upwards force.

The object only floats when this upwards force beats the weight of the object.

And that only happens when the object's density is lower than the air's.

If you want to know more, google buoyant force and stop annoying others. The math is there and it's simple.

[Anonymous No.9316382]

>>9316365
Okay Mr. Smart, then what would happen if the balloon was filled with normal air, but the surface of the balloon was made of Helium. Where would it go?

[Anonymous No.9316396]

>>9316339

Therefore atmospheric pressure = gravity? What differences do they have exactly?

[Anonymous No.9316412]

how do I find this limit? it should be -oo

[Anonymous No.9316419]

>>9316382
into the sun, where it would sink because air is denser than the sun's helium.

[Anonymous No.9316423]

>>9316396
not really.

atmospheric pressure is a function of altitude, and that's because we are in a gravitational field that's oriented vertically.

[Anonymous No.9316427]

>>9316412
it goes to -infinity indeed.

(x+1) goes to 1

ln(x) goes to -infinity

sin(x) goes to 0+

1*(-infinity)/(0+) = - infinity

[Anonymous No.9316430]

>>9316427
*barfs

[Anonymous No.9316434]

>>9316427
isn't that an undeterminate form?

[Anonymous No.9316438]

>>9316412
Try l'Hôpital

[Anonymous No.9316442]

>>9316438
l'hopital doesn't always work if it's not an undeterminate form.

this one trivially diverges to -infinity

[Anonymous No.9316448]

How much is 1+1?????

[Anonymous No.9316453]

>>9316423

That's just a long-winded way of saying atmospheric pressure is gravity.

[Anonymous No.9316454]

>>9316199
Polemicist

[Anonymous No.9316582]

>>9316173
Experimental psychology/statistics question.

I've got a quasi independent variable (dichotomous/yes or no question) that I'm examining the correlation with an interval (continuous) dependent variable.

I am running a second correlation that uses the same quasi independent variable from the first correlation, but this time it's the dependent variable. Can you flip a quasi IV like that to a regular dependent variable in a separate correlational/nonexperimentall test?

[Anonymous No.9316602]

If something moved at speed 3c from point A to point B and back to A, would there be any way to verify that the something did that and was not stationary?

[Anonymous No.9316634]

>>9316602
>If something moved at speed 3c from point A to point B and back to A, would there be any way to verify that the something did that and was not stationary?
Don't take my answer for a good one. I am just another hobbyman.
Provided that could happen (it can not), I guess the object would disappear forever, since B, A, or any point its movements, would be located in undefined time in the future ("infinite").

If you try to put those numbers in a lorentz transformation, you will see that you end up with weird things like "imaginary time".

[Anonymous No.9316668]

>>9316427
>infinity
No such thing.

[Anonymous No.9316743]

>>9316668
true

it's just a thought experiment of course. I'm not limited in my ability to entertain thoughts based on inexistant objects.

[Anonymous No.9316747]

>>9316743
Just assume [math]0 = 1[/math] next time and get the theorem you want. It's a lot easier.

[Anonymous No.9316756]

When are tidal gauges going to show significant acceleration in water level rise? Lets say 10% faster over 30 years than the early part of the 20th century (which was before oil use grew explosively).

Give me a prediction, maybe I'll remember it at old age and get a laugh "fucking morons like that was what we destroyed our economy for".

[Anonymous No.9316764]

>>9316747
I can do that, but the guy asking can't.

[Anonymous No.9316767]

>>9316764
>I can do that, but the guy asking can't.
I'm not a "guy".

[Anonymous No.9316769]

>>9316764
Why not? He's already assuming something provably equivalent.

[Anonymous No.9316778]

>>9316767
You're not the guy he is talking about either, faggot.

[Anonymous No.9316788]

>>9316756
Global warming myth BTFO!

[Anonymous No.9316797]

>>9316767
couldn't care less, guy.

[Anonymous No.9316805]

>>9316797
I'm not your "guy", buddy.

[Anonymous No.9316817]

>>9316448
this is /sqt/, you should try /mg/

[Anonymous No.9316818]

>>9316805
I'm not your buddy, pal.

[Anonymous No.9316823]

>>9316797
Just report the retard, he has been shitting up every single thread on this board.

[Anonymous No.9316827]

>>9316823
>retard
Why the ableism?

[Anonymous No.9316828]

>>9316818
Well I'm not your "pal", friend.

[Anonymous No.9316895]

>>9316396
>>9316453
Atmospheric pressure is created by the effect gravity has on gasses.

[Anonymous No.9316915]

>>9316895
wait I have the farts because of gravity? neet

[Anonymous No.9316930]

Trying to figure out some good places to mutate in this protein in order to see if it'll take in different amino acid substrates. I'm looking at this protein sequence alignment for guidance, but I'm having trouble understanding it. Anyone have any tips for doing shit like this?

[Anonymous No.9316946]

Someone post the picture with the math books pls

[Anonymous No.9316961]

What board is smarter, /lit/ or /sci/?

[Anonymous No.9316964]

>>9316961
>What board is smarter, /lit/ or /sci/?
/pol/

[Anonymous No.9316974]

>>9316964
>>>9316961
>>What board is smarter, /lit/ or /sci/?
>/pol/
/b/

[Anonymous No.9317071]

>>9316306
Do you know the boundary conditions at infinity?
If you do then do a Fourier transform.
>>/sci/thread/S9263958#p9264355

[Anonymous No.9317076]

>>9316961
Neither

[Anonymous No.9317159]

Are animals likely to experience heat from chilli and cold from menthol?

[Anonymous No.9317160]

>>9316245
The bigger the penis the better for pumping out other mens sperm. They think that why humans have proportionately much bigger penises than other animals, it's because the women were sluts and the biggest dick removed the most semen.

[Anonymous No.9317168]

Is it gonna rain today

[Anonymous No.9317169]

>>9317160
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4888289/

It's also why the human penis is shaped like a plunger and other animals are not.

[Anonymous No.9317208]

>>9317159
>Capsaicin is also used to deter pests, specifically mammalian pests. Targets of capsaicin repellants include voles, deer, rabbits, squirrels, bears, insects, and attacking dogs.[48] Ground or crushed dried chili pods may be used in birdseed to deter rodents,[49] taking advantage of the insensitivity of birds to capsaicin. The Elephant Pepper Development Trust claims the use of chili peppers to improve crop security for rural African communities[citation needed]. Notably, an article published in the Journal of Environmental Science and Health in 2006 states that "Although hot chili pepper extract is commonly used as a component of household and garden insect-repellent formulas, it is not clear that the capsaicinoid elements of the extract are responsible for its repellency."[50]

It appears that capsaicin exposure doesn't effect birds, but most other mammals can feel it.

[Anonymous No.9317296]

Is there a scientific explanation as to why meme-"depression" feels so good?

[Anonymous No.9317316]

>>9317296
https://en.wikipedia.org/wiki/Catharsis

[Anonymous No.9317406]

I don't know which board to post this on. It's related to video games but /v/ is such a garbage ass board that I won't even bother

Could there be a connection between one's capacity for empathy and being good at multiplayer video games?

I'm quite empathetic as a person. I'm very good at reading people's emotions and moods just from their non-verbal behavior, and upon reading stuff like news stories I involuntarily end up feeling like shit when I read about bad stuff happening to people.

Now coincidentally, I'm very good at multiplayer games, but specifically only the multiplayer aspect. It feels like I can very often predict what people are going to do, and that allows me to outmaneuver them. I can also tell when people are upset or frustrated, which I can usually use to my advantage in some way. I usually beat people by getting into their heads and overwhelming them by predicting their moves. However, I'm horrible against intelligent AI opponents if they're not completely predictable, and also pretty bad against players who have a non-sensical playstyle. I try to predict their actions, but there's nothing to predict since they do things randomly. When it comes down to it, I'm mechanically not that great of a player, I just have good intuition and predictive abilities.

[Anonymous No.9317427]

>>9316602
No, there isn't.

[Anonymous No.9317587]

Could someone please explain to me valancy and valance elections and the difference between them please.

[Anonymous No.9317731]

>>9317071
I only know u(0)=0=u'(1), where u is the function I could solve if I had the Green's function and knew what function the operator turns u into.

[Anonymous No.9317815]

Can any mathematicians help a physics brainlet out?

I'm trying to derive the stability conditions for the Lorenz attractor generally. The way to go about this for a typical flows problem is to find the Jacobian and solve for its eigenvalues. If the real part of all of the eigenvalues is negative, then all flows at points close to the stationary point go into the point, so it is stable.

The Lorenz attractor is a 3D problem, so we get a cubic polynomial to solve for the eigenvalues. The problem is characterised by three real parameters, which give rise to three degrees of freedom in the polynomial, so the set of possible polynomials is all of the cubic polynomials with real coefficients, which we can write as

[math]x^3 + Ax^2 + Bx + C = 0[/math]

where A, B and C are real.

The problem essentially boils down to this: What are the conditions on A, B and C such that the real part of all the roots of the polynomial is less than 0?

I made a bit of a start but didn't get too far. I set the roots to be -a, -b and -c, where a is real and b and c may be complex (in the case in which they are, c = b*). We thus write the polynomial as

[math](x+a)(x+b)(x+c) = 0[/math]

thus

[math]A = a + b + c, B = ab + bc + ac, C = abc[/math]

And we want to ensure that a, b and c have a positive real part.

I can't get much further than this. Obviously C must be positive, or else an odd number a, b or c would be negative, but once I have that condition I can't find another one that restricts the sign of the other two roots.

[Anonymous No.9317834]

>>9317815
without loss of generality you can assume
[math] a,x,y \in \mathbb{R},~b = x+iy,~c=x-iy [/math]
Since it's a polynomial with real coefficients.
This gives you
[math] A = a+2x >0 [/math]
[math] B= x^2+2ax+y^2 >0 [/math]
and
[math] C = a(x^2+y^2) > 0 [/math]
Note that those conditions are not sufficient, but if they are not met, you won't have positive real parts

[Anonymous No.9317841]

>>9317834
let me correct myself
>without loss of generality
is not exactly true.
You could also have 3 purely real roots, which also gives you the same necessary but not sufficient conditions for A and B

[Anonymous No.9317849]

>>9317587
Anyone?

[Anonymous No.9317871]

>>9317587
Valence electrons are electrons in the outermost shell of the atom.

They're the ones that actually do shit like forming bonds with other atoms, so the number of valence electrons determines the chemical properties of an atom or molecule.

[Anonymous No.9317946]

If [math]lim_{x\rightarrow\infty}f(x)=\infty[/math], does this imply [math] lim_{x\rightarrow\infty}f'(x)\neq0[/math]?

[Anonymous No.9317949]

>>9317946
No. Consider f(x) = log(x)

[Anonymous No.9317950]

>>9317946
consider f(x) = log(x)

[Anonymous No.9317954]

>>9316946

[Anonymous No.9317977]

>>9317954

[Anonymous No.9317981]

>>9317954
>he/she posted the memelist again

[Anonymous No.9317984]

>>9317954
Please add a disclaimer: DO NOY TRY TO READ MORE THAN THE FIRST PART OF JECH

[Anonymous No.9317986]

>>9317984
>DO NOY TRY TO READ MORE THAN THE FIRST PART OF JECH
Why not?

[Anonymous No.9317997]

Which degree is harder- applied math, pure math, or statistics?

t. brainlet

[Anonymous No.9318057]

>>9317997
They're probably equally hard.
I don't know about statistics, but if you're gonna spend years studying, I am pretty sure you will encounter some really hard shit.

[Anonymous No.9318067]

>>9317997
They're all different man!

I think your best option, for a BS, is to do Applied Math and make sure you get your Analysis/Advanced Calculus sequence in. That's not a hard class but it's the meat and potatoes of the math world and lets you do a lot of stuff in statistics.

I did Applied Math for undergrad, Pure Math for my MS (because that's all my school has) and now i'm applying to Stats PhDs.

Studying Pure Math isn't super hard but it's really abstract. Studying stats is hardest I think, cause they make you take a lot of tests.

[Anonymous No.9318082]

is ln(x) = e^ln(x) correct?

[Anonymous No.9318086]

>>9318082
>is ln(x) = e^ln(x) correct?
No.

[Anonymous No.9318087]

[math]f'(f(t)) = ct[/math]
What does this expression say about [math]f(t)[/math] and [math]f'(t)[/math]?

[Anonymous No.9318106]

>>9318087
f can't be polynomial (except trivially 0)

[Anonymous No.9318109]

>>9318087
if f is analytic, then f = \pm \sqrt(c)t

[Anonymous No.9318112]

>>9318087
>>9318109
uhh nvm f can't be analytic

[Anonymous No.9318113]

>>9318086
what if this was say any programming language and I just define a function called log ( x ) as a function that takes the constant "e" and does e^x where x is just a new call to the function

would this replicate the behaviour of the logarithmic function?

[Anonymous No.9318116]

>>9318113
what the fuck are you even saying

[Anonymous No.9318127]

>>9318106
>f can't be polynomial (except trivially 0)
can't be a Laurent polynomial either

[Anonymous No.9318130]

>>9318116
how is ln(x) formally defined?

[Anonymous No.9318133]

>>9318130
>how is ln(x) formally defined?
https://en.wikipedia.org/wiki/Logarithm#Definition

[Anonymous No.9318134]

>>9318130
two ways. once is the inverse of exp. the other is the antiderivative of 1/x with ln(0) = 1

[Anonymous No.9318137]

>>9318133
>>9318134
thanks guys

maths is fucking insane

[Anonymous No.9318140]

>>9318106
Can it be exponential? When I read it out loud I get "the rate of change of f is linear with respect to f", and that to me sounds like it could describe an exponential function when c is positive but I can't get that down on paper. I am a brainlet and my intuition here is probably flawed.

[Anonymous No.9318147]

>>9318087
A solution is [math] f(t) = t^{\phi}, c = \phi [/math]

[Anonymous No.9318146]

>>9318140
>Can it be exponential?
No, if f(t)=a*e^(bt) then f'(t)=ab*e^(bt) and
f'(f(t))=ab*e^(ba*e^(bt)) is definitely not linear

[Anonymous No.9318159]

>>9318146
Yeah, that was the problem I was having, which is why I have to think there's something wrong with my intuition here. Dunno if you can write out a more enlightening way to read the expression, but otherwise thanks for the help.

>>9318147
Thank you too.

[Anonymous No.9318162]

>>9317984
>>9317954
>>9316946
I was definitely a bit wrong on putting Jech there, but I didn't know where else to put it when I made it. I edited it so it's not a complete meme anymore

[Anonymous No.9318164]

>>9318159
>Thank you too.
No problem. It is good intuition to always test if x^n works, differential equations taught me that, and in this case it works as long as n^2 - n - 1 = 0 which gives the golden ratio. That's two solutions. I tried proving those are the only solutions but nothing works. You are on your own now. Good luck.

[Anonymous No.9318169]

I just realized I don't actually understand anything about linear algebra or calc and was just memorizing shit.

Is this alright for an engineer, if not how do I fix 3 years of supposed knowledge?

[Anonymous No.9318179]

>>9318164
>That's two solutions. I tried proving those are the only solutions but nothing works. You are on your own now. Good luck.
Those are definitely two solutions, and maybe I did something wrong but I don't think you need c=phi, any constant should do the job?

[Anonymous No.9318185]

>>9318179
Yeah, you are right. If you set f(t) = a x^(phi) that is also a solution and then you can vary the constant a to ger any c.

So really what remains to show is if x^(phi) generates all solutions or not.

[Anonymous No.9318188]

>>9318147
>[math] c \left ( t^c \right ) ^{c-1} = ct [/math]

[Anonymous No.9318192]

>>9318188
Yes, if c is the golden ratio. Have you graduated highschool?

[Anonymous No.9318206]

Where do you guys get your energy to concentrate?
I can barely keep my eyes open for 1 hour straight, despite eating healthy and working out.
Am I doing something wrong?

[Anonymous No.9318251]

>>9318192
most people here haven't unfortunately.

[Anonymous No.9318281]

>>9318251
I suppose. But I don't know about that guy. Knowing the golden ratio is a pretty low bar. I don't know what someone who does not know about it is doing here. Maybe he is some /pol/fag with no math education who just comes here to spam. Who knows.

[Anonymous No.9318291]

>>9318281
who knows... probably the correlation-causation guy

>Inb4 I'm not a "guy"

[Anonymous No.9318293]

>>9318206
meth

[Anonymous No.9318319]

>>9318130
ln(a) is the area under the graph of 1/x given that you start 1 and you end up at a. If a is to the left of 1 then you give that area a negative sign.
[math] \ln(a) = \int_{1}^{a} \frac{1}{x} dx [/math]

[Anonymous No.9318320]

>>9316895

So if nitrogen has more mass than oxygen, why doesn't nitrogen rise as well? That goes for everything that has less mass than the air too.

[Anonymous No.9318335]

>>9318320
>So if nitrogen has more mass than oxygen, why doesn't nitrogen rise as well? That goes for everything that has less mass than the air too.
If the buoyant force is small compared to the thermal agitations, Dalton's Law dominates and the gasses mix freely.

[Anonymous No.9318363]

>>9316173
I've got a question about electrons. If circuits rely on the transfer of electrons from one substance, that substance loses it's electrons, yes? If this is the case, why electrons necessary in a substance?

[Anonymous No.9318380]

>>9318363
>why electrons necessary in a substance?
They're not exactly, it's the protons that really determine it, and an atom with greater or fewer electrons or neutrons is considered an ion or an isotope, respectively, of that element. Electrons move very freely, but in a neutral state they match the number of protons in the nucleus.

[Anonymous No.9318388]

>>9318363
>If circuits rely on the transfer of electrons from one substance,

no they rely on movement of charges. Charges can be electrons, holes, ions.

>that substance loses it's electrons, yes?

no, because you need a close circuit, meaning if you push out electrons (or any other charge) out, you're also pushing in electrons from somewhere else.

>If this is the case
so it's not the case, electrons are safe.

[Anonymous No.9318421]

>>9318388
Don't electrons need to be moved somehow in order to even create a potential difference?

[Anonymous No.9318452]

>>9316173
What are some disadvantages of cross-linking polymers? i.e making polymer chains

[Anonymous No.9318493]

>>9318452
Too much cross-linking will alter your material properties e.g. rubber being too hard

[Anonymous No.9318503]

How do I use the invariant tensors [math]\delta^i_j, \epsilon_{ijk},\epsilon^{ijk}[/math] to decompose tensor products in SU(3)? An example is given in:
https://physics.stackexchange.com/questions/102554/tensor-decomposition-under-mathrmsu3

[Anonymous No.9318512]

>>9318421
you might want to look at a Daniell cell and read up on how it works.

In any case there's no need to break conservation of charge.

If something goes out of a wire, something else has to go in just to push the first thing out/sucked in by what left because the wire is a conductor.

[Anonymous No.9318522]

>>9318512
I think the question was about electrons being moved away from a particular substance without altering the substance, not charge escaping from entire system, but I might be wrong.

[Anonymous No.9318532]

>>9318522
I don't understand the question then.

If that person still has an issue they need to precisely account for everything when they ask so that we have a proper discussion.

popsci videos are doing too much harm.

[Anonymous No.9318537]

>>9318532
From what I could tell his misunderstanding was that the number of electrons is fundamental to a substance and that it would be a different substance with any other number, but again I can't be certain.

[Anonymous No.9318545]

>>9318493
thank you

[Anonymous No.9318641]

My teacher gave the following definition for a limit point: Given a set S, a limit point of S is such that any open interval about the point intersects S, or
x is a limit point [math] \leftrightarrow \forall \varepsilon >0\ B_{\varepsilon}(x) \cap S \neq 0 [/math]

Don't all interior points satisfy this definition? Isn't this only true if the open interval about the point is also not a subset of S?

[Anonymous No.9318647]

>>9318641
>Don't all interior points satisfy this definition?
Yes.

> Isn't this only true if the open interval about the point is also not a subset of S?
Not sure what you're getting at here

[Anonymous No.9318660]

>>9316930
the active center, locate its sequence stretch

[Anonymous No.9318665]

>>9318647
yeah forget that second part, that would mean that closed sets don't have limit points. But how can interior points be limit points? That's the same definition I found online.

[Anonymous No.9318680]

>>9318665
>how can interior points be limit points
they just are (in usual topology of R^n)

[Anonymous No.9318698]

>>9318665
> But how can interior points be limit points?
for all epsilon>0 we have x \in B_epsilon(x)\cap S

boundary points are also limit points of S for the same reason

[Anonymous No.9318715]

>>9318680
ok so my teach also said that an interior point of S is such that any open interval is contained within S. Doesn't that mean that all sets with gaps between elements (like [math] \N [/math]) don't have interior points, since an interval around 0, which contains -.5 and .5, is not a subset of [math] \N [/math]?

[Anonymous No.9318738]

>>9318715
what's the topology of N? (written \mathbb{N} btw) if it's the topology induced from R, then the unitary sets {n} are open for any n, and any point is an interior point. the "gap" just isn't there

[Anonymous No.9318831]

>>9318738
>if it's the topology induced from R, then the unitary sets {n} are open for any n,
wtf are you talking about
that's plain wrong
>and any point is an interior point.
no

[Anonymous No.9318839]

>>9318715
>. Doesn't that mean that all sets with gaps between elements (like N) don't have interior points
For N, yes.
But not for Q for example.

>since an interval around 0, which contains -.5 and .5, is not a subset of N
That's not a justification.
It is that Any open interval around 0 is not a subset of {0}.

[Anonymous No.9318840]

>>9318831
it is. N is a discrete set in R, and the induced topology will be the discrete topology.

[Anonymous No.9318849]

>>9318840
Oh you meant open in N. My bad.

[Anonymous No.9318889]

>>9318512
> If something goes out of a wire, something else has to go in just to push the first thing out/sucked in by what left because the wire is a conductor.

That isn't strictly true. It's possible for body to have a net charge (i.e. too many or too few electrons relative to the number of protons). But a charged body will exert forces on electrons which will tend to restore equilibrium (i.e. a body with too many electrons will repel electrons, one with too few electrons will attract electrons).

So as you start removing electrons from a conductor, you need progressively more electromotive force (voltage) to remove additional electrons, or even to prevent electrons from returning.

[Anonymous No.9318974]

Talking about finite state machines, can a final state have any transitions to other states to fulfill the next example? Let's say that I want a machine that represents all chains consisting on "aba" at least once; so that can be aba, abaaba, abaabaaba, etc. So my machine looks like this:

INITIAL STATE - Output a goes to STATE 1
STATE 1 - Output b goes to STATE 2
STATE 2 - Output a goes to STATE 3
STATE 3 - Output a goes to STATE 2

In my mind this would work, and the third state is the final. Does this make sense or am I breaking some rule?

[Anonymous No.9318996]

Are the Feynman Lectures on Physics good to learn from?
I got the pdf of exercises book too

I studied Physics a long time ago. I know calculus.

[Anonymous No.9319011]

>>9318996
>I know calculus
The "I like turtles" of the physics world, everyone.

[Anonymous No.9319013]

>>9319011
t. the asshole of the /sci/ world, everyone

[Anonymous No.9319057]

why do I feel sexually attracted to anime girls

are they the idealized version of female mating partnets

[Anonymous No.9319061]

>>9319057
partners*
fuck i cant spell on phone

[Anonymous No.9319065]

How do I get into a good grad school for cs . Are German universities better than US universities?

[Anonymous No.9319218]

>>9318974
> Talking about finite state machines, can a final state have any transitions to other states
Assuming that "final state" just means "accepting state", then yes. In general, if a string is a valid word in itself and can also be a prefix of a longer word, there will be an accepting state with transitions.

For a NFA, it will always be possible to construct an equivalent NFA where accepting states never have transitions: just duplicate any accepting states (including their inward transitions but without any outward transitions). This isn't possible for a DFA (duplicating a state along with its inward transitions would make it non-deterministic).

[Anonymous No.9319227]

>>9319057
my autistic hypothesis: with every lowering dimension our standards for perfect decrease exponentially

[Anonymous No.9319242]

What's the best current methods of life extension that don't negatively impact brain function?

What's a good field of study for a ~125-130 IQ introvert that will pay for life extension in the short term and help the eventual intergalactic colonization in the long term?

[Anonymous No.9319252]

So, I'm doing resonance in organic chem. One thing that's puzzling me is- when you move electrons for resonance structures, you apparently can break octet rule temporarily as electrons jump around. How is this physically possible?

[Anonymous No.9319255]

>>9319227
holy shit this actually makes sense.

you can fuck up an (n+1)-dimensional thing in many more ways than an n-dimensional thing

[Anonymous No.9319262]

I'm having a little problem trying to understand frequency.

Frequency is the quantity of cycles that an event occur during certain time. Cycle is the time during which an event starts and finish. If both deals with time, why frequency's unit is hertz ([math]\frac{1}{s}[/math]) and not something like [math]hertz^2[/math] (that would be [math]\frac{1}{s^2}[/math]). I'm looking for, I guess, a definition of frequency and a meaning of "cycle" with better choice of words, because words are what is getting me confused.

[Anonymous No.9319269]

I'm having a little problem trying to understand frequency.

Frequency is the quantity of cycles that an event occur during certain time. Cycle is the time during which an event starts and finish. If both deals with time, why frequency's unit is hertz ([math]\frac{1}{s}[/math]) and not something like [math]hertz^2[/math] (that would be [math]\frac{1}{s^2}[/math]). I'm looking for, I guess, a definition of frequency and a meaning of "cycle" with better choice of words.

My apologies in advance for being a brainlet that overthinks the meaning of words.

[Anonymous No.9319286]

>>9319269
Frequency is the number of cycles per second lmfao.

[Anonymous No.9319315]

>>9319286
Right. Now what is a cycle?

[Anonymous No.9319319]

>>9319315
Are you fucking serious?

[Anonymous No.9319334]

>>9319319
Nevermind. I'm gonna go check a dictionary.

[Anonymous No.9319553]

What exactly is deacceleration?

Is it referencing when the acceleration itself is negative? What if the acceleration is positive, but the derivative of acceleration is negative? Or vice versa? Does that still count as deacceleration? I asked this once in lecture during statics and dynamics and I was never given an answer.

[Anonymous No.9319555]

>>9319553
Deceleration is just what we would call accelerating in the vector opposite of your current velocity. So you could represent that as negative acceleration in the same direction as your velocity.

[Anonymous No.9319558]

>>9319555
So in other words the derivative of acceleration is irrelevant then, correct? I was just wondering if it had any bearing.

[Anonymous No.9319561]

>>9316199
https://www.tfd.com/Choleric

[Anonymous No.9319562]

Could someone please explain why is it easier to pull electrons from bigger atoms?

[Anonymous No.9319568]

>>9319562
Not as stable due to the strong force. There are also numbers which are extremely stable such as lead and oxygen. The electron configuration is also important to consider becouse s and p level are traditionally more stable than d or f which typically occur in more heavy elements.

[Anonymous No.9319578]

>>9319568
But physically shouldn't bigger objects attract more electrons rather than easily give them away (Bigger=higher gravity)?

[Anonymous No.9319590]

>>9319578
>higher gravity
Gravity doesn't exist in any real way.

[Anonymous No.9319600]

>>9316236
Try it, write a report and post it here.
For science!

[Anonymous No.9319612]

would learning category theory give me the best bang for buck in learning a lot of other areas of math like geometry, analysis, and algebra?

[Anonymous No.9319618]

>>9319612
it's useful for algebraic thingies
useless for anything analytic

[Anonymous No.9319624]

What's the difference between right and left, in a more rigorous sense than
>le it's all relative and arbitrary bro
I want to know why we are intuitively capable of making this distinction.

[Anonymous No.9319630]

>>9319624
your heart is on your left side.

[Anonymous No.9319634]

>clouds are water vapor
>okay
>water only becomes vapor/steam when boiling
>clouds are boiling water
I get there is a difference in boiling temperature with levels of pressure but still, what are clouds?

[Anonymous No.9319654]

>>9316199
Nigger?

[Anonymous No.9319661]

>>9319252
I assume that by "breaking the octet rule" you mean the formation of charges? You should keep in mind that resonance structures are not exactly real - all of the possible resonance structures basically try to approximate the electron density of a molecule. So like in pic related, the C atom has a + charge in one of the structures, but the acrolein molecule does not necessarily have a true + charge. Resonance structures are useful in predicting reactivity, like nucleophiles will most likely attack acrolein in the C atom with the + charge in one of the resonance structures.

>>9319562
It's largely a function of distance, electrons in orbitals farther from the nucleus are less influenced by the attractive Coulombic force. There's also the matter of shielding, where atoms in the inner orbitals "shield" the outer electrons from the positive nucleus which means they are less tethered to the atom.

[Anonymous No.9319663]

>>9319624
Swap (x,y) with (-y,x), that's left. Swap it with (y,-x), that's right.

Or more generally, use rotation matrices. (0,pi) is left, (0,-pi) is right.

[Anonymous No.9319688]

>>9319661
Thank you so much!!

[Anonymous No.9319700]

are there any good introduction book for a brainlet to understand the following in successive order:

universal algebra

higher algebra

group theory (including generalizations)

representation theory

algebraic approaches to differential calculus

homological algebra

general topology

algebraic topology

homotopy theory

rational homotopy theory

differential geometry

differential topology

algebraic geometry

noncommutative algebraic geometry

noncommutative geometry (general flavour)

higher geometry

Lie theory

[Anonymous No.9319752]

>>9319558
No, it has a name: jerk. Its own derivative is jounce.

[Anonymous No.9319768]

>>9319612
>areas of math like geometry, analysis, and algebra?
But geometry and analysis aren't areas of math. For algebra you'll have to learn it either way if you're even half decent.

[Anonymous No.9319804]

>>9319768
>But geometry and analysis aren't areas of math
What?

[Anonymous No.9319830]

>>9319804
What is confusing you?

[Anonymous No.9319935]

what does the f stands for in the values of saturated liquid, or the g for those of vapor?

[Anonymous No.9319960]

>>9319700
>group theory (including generalizations)
mark armstrong - groups and symmetry

>representation theory
vinberg - Linear Representations of Groups

> algebraic topology
Sergey V. Matveev - Lectures on Algebraic Topology

>algebraic geometry
garrity - algebraic geometry a problem solving approach

> Lie theory
stillwell - naive lie theory

[Anonymous No.9320135]

>>9319661
Thanks chemanon!

[Anonymous No.9320161]

What's the relationship between molar mass and vapor pressure? If I increase molar mass then vapor pressure goes down right? But why?

[Anonymous No.9320207]

>>9320135
>>9319688
No problem dudes

>>9320161
Vapor pressure is inversely related to the intermolecular forces of attraction. One type of IMFA is the London dispersion force, which is dependent on the polarizability of the molecule. Polarizability is how easily the electrons of the molecule can be distorted, and is directly related to the size and molar mass of the atom or molecule. London dispersion forces are significant for nonpolar molecules, which explains the trend in dihalogens: the lighter F2 and Cl2 are gases, mid-weight Br2 is a liquid, and the heavier I2 is a solid at standard temp and pressure.

[Anonymous No.9320242]

>>9320207
Thanks! The experiment I did in the lab used alcohols (methanol and ethanol). Could you explain how London dispersion forces work for alcohols, or is there a different IMF at work?

[Anonymous No.9320304]

>>9319286
>>9319315
Frequency is the number of <whatever>s per second.

A cycle is basically anything that keeps repeating.

[Anonymous No.9320461]

I feel like I don't really get chemistry cuz I don't understand the physics of electrons. Is there any good way to learn this from grounds up?

[Anonymous No.9320494]

>>9320242
For both alcohols, hydrogen bonds are more predominant. But since they have the same functional group, the difference in BP stems from their alkyl chains. Dispersion forces are at work for hydrocarbon chains, and since ethyl chains are larger than methyl groups, dispersion forces have a larger effect for EtOH, explaining the higher BP.

[Anonymous No.9320527]

>>9319612
No.
If you haven't learned geometry and analysis yet you are not mathematically mature enough to understand these texts.

And trying to learn algebra before category theory is downright insane, since it the assumed knowledge you need to understand these texts at all.

[Anonymous No.9320529]

>>9320527
>And trying to learn algebra before category theory is downright insane
uh

[Anonymous No.9320536]

>>9320527
Pretty sure you mean "trying to learn category theory before algebra is downright insane"

>>9320494
What is BP?

[Anonymous No.9320545]

>>9320529
>>9320536
Yes of course I meant "learning category theory before algebra", I should go to sleep.

[Anonymous No.9320557]

>>9320536
>what is BP
boiling point

[Anonymous No.9320672]

>>9316173
What volume is my internal monologue?

[Anonymous No.9320685]

>>9320672

it has no volume because it's not a sound wave.

[Anonymous No.9320691]

>>9320685
>it has no volume because it's not a sound wave.
What does it have then? It's certainly not a whisper or a scream

[Anonymous No.9320703]

will we ever have a widely accepted and plausible theory for what happened in the planck epoch/before the big bang

[Anonymous No.9320720]

>>9320703
"Before" isn't even a useful metric here, as we're pretty sure time itself began during the Big Bang.

[Anonymous No.9320724]

>>9320703
the only reasonable way is if can ever reproduce similar conditions in a lab.

whatever comes out of that would be the best explanation.

[Anonymous No.9320727]

>>9320720
>we're pretty sure time itself began during the Big Bang.
Speak for yourself.

[Anonymous No.9320736]

>>9320691
It's recreating the mechanical/chemical aspects of listening that happen in the brain itself, most importantly the language processing where meaning is attributed to the sounds, where the meaning is independent of the volume. Maybe you've had the experience of having said something and, once it's gone out of sensory memory, you remember what you said but can't remember how loudly you said it.

[Anonymous No.9320754]

>>9320720
then how did the big bang happen if there was no passing time to go from "pre-big bang" to "big bang"?

[Anonymous No.9320762]

>>9320754
To answer that, we'd need to know what laws of physics were in operation outside of our own space-time continuum.

[Anonymous No.9320776]

>>9320754
In that case there is no "pre-big bang", you could just as well think of it as existing spatially, where our universe at every point in time as we experience it existed all at once in a timeless space. Not to draw any direct comparison between that and our experience of space, just an analogy.

[Anonymous No.9320794]

>>9318996
To what extent do you know calculus?
>>9319612
It'll give you a superficial understanding of other areas of math and all you'll be capable of doing is abstract wank that serves no purpose. For instance there's no way for anyone to extract the definition of functional germs from the categorical definition of a sheaf, and the latter isn't nearly as useful (or even usable) in the algebraic geometry of Riemannian surfaces as the former.

[Anonymous No.9320906]

PLS help finish proof.

Prove [math]\frac{x^n}{1+x+x^n} [/math] converges uniformly to f(x) = 1 on 0<x<1.

I have:
[math]|\frac{x^n}{1+x+x^n} -1|=|\frac{x^n-1-x-x^n}{1+x+x^n} |=|\frac{-1-x}{1+x+x^n} |=|\frac{1+x}{1+x+x^n} |[/math]

Now I'm not sure where to go so I start fuckin around

[/math]\leq |\frac{1+x}{x^n} |\leq |\frac{2}{x^n} |[/math]

Not sure what to do with this

[Anonymous No.9320910]

>>9320906
Fixed latex on the second part:

[math]\leq |\frac{1+x}{x^n}|\leq |\frac{2}{x^n} |[/math]

Not sure what to do with this

[Anonymous No.9320913]

Fuck you how to relate [math]\|u\|_{L^2(U)}[/math] and [math]\|u\|_{L^2(\partial U)}[/math]? Preferably looking for a theorem that says both differ by at most a constant factor.

[Somebody Else No.9320941]

>>9320906
It doesn't converge to 1 in that open interval, it converges to 0.

[Somebody Else No.9320948]

>>9320941
(That is, assuming you want n to go to infinity)

[Anonymous No.9320982]

>>9320913
Green's theorem.

[Anonymous No.9320989]

>>9320913
trace theorem for sobolev spaces?

[Anonymous No.9321041]

>>9320989
Yes that's the one I'm looking for thanks

[Anonymous No.9321054]

>>9320906
like >>9320941 said, it converges pointwise to 0.
It doesn't converge uniformly, since [math]f_n(1) = \frac{1}{3} [/math] for all n and since it's continuous there's always a point in (0,1) where the function takes a value that is arbitrarily close to [math] \frac{1}{3} [/math]

[Anonymous No.9321110]

>>9321054
I don't think that's true.

[math]\frac {x^n}{1+x +x^n} < \frac {x^n}{1+x} < \frac {x^n} 1[/math] for 0 < x < 1, and the last one obviously converges to 0 as n goes to infinity, so it uniformly converges to 0

[Anonymous No.9321122]

How are negations, disjunctions and implications proven in Gentzen's LJ system?

[Anonymous No.9321127]

>>9321110
How do you prove that with epsilons n sheit? If we have:

x^n

Then the N we choose depends on x, which means it doesn't converge uniformly on (0, 1).

[Anonymous No.9321129]

>>9321110
read up on your definitions
[eqn]\lim_{n\to\infty} \sup_{x\in(0,1)} \left |\frac {x^n}{1+x +x^n} - 0 \right | = \frac{1}{3} \neq 0 [/eqn]

[Anonymous No.9321160]

>>9321127
>>9321129
Oh, I never heard about uniform convergence before and just assumed it means "converges to the same value for all x in the interval"

[Anonymous No.9321286]

Guys I supposed to get this as an answer instead I get 12.18 on my calculator, do I have set my calculator on a different mode? My calculator's Casio fx-300ms

[Anonymous No.9321318]

Hey guys, brainlet here, can any of you show me how to solve this problem? Idk how to find the inverse Fourier transform of this because idk what the vale of delta(omega) is

Much appreciated

[Anonymous No.9321323]

>>9316173
I just noticed that all maths objects can be defined only in terms of operations we can perform on them.
Is there some hidden meaning of it, or I just realised something obvious.

[Anonymous No.9321326]

>>9321286
how are you typing that in? or are you simplifying the expression in any way?

you seem to be evaluating e^(5/2) which makes me think that you are doing something like -6 + sqrt(36) + sqrt(e^5)

[Anonymous No.9321339]

>>9321323
Have you looked at type theory at all?

[Anonymous No.9321342]

>>9321326
I just type e5, get an error if I type e^5, I need to set on a different mode don't know which

[Anonymous No.9321352]

>>9321339
ofc no

[Anonymous No.9321356]

>>9321352
Well what you said sort of reminds me of the introduction to Russell and Whitehead, so there may be something in there of value to you.

[Anonymous No.9321382]

What is the symbol c referred to by #A = 'c' in this picture?

[Anonymous No.9321394]

>>9321318
isn't that function basically equal to [math] \frac{\pi}{10} \delta (\omega)[/math]?

In that case the inverse transform would be pi/10

[Anonymous No.9321396]

>>9321382
cardinality of A (number of elements in A)

[Anonymous No.9321400]

>>9321318
Could you zoom it in a little more?

[Anonymous No.9321401]

>>9318660
So just compare the active site amino acid to other proteins then?

[Anonymous No.9321402]

>>9321396
Sorry I know it's cardinality but what size does c refer to?

[Anonymous No.9321422]

>>9321402
oh sorry I misread

it's the cardinality of [math] \mathbb{R}[/math], [math] 2^{\aleph_0}[/math]

[Anonymous No.9321423]

>>9321400
Wait what lol? The equation shown is the whole thing

>>9321394
Could you explain please

[Anonymous No.9321436]

>>9321326
>>9321286
Ok this how I'm typing on calculator -6+√36+√e^5, I supposed to get 7.580 but I get 12.18

[Anonymous No.9321440]

>>9321423
think about the values of that function.

if [math] \omega \neq 0 [/math], then the whole thing is equal to 0.

The only place where it's not 0 is when [math]\omega = 0[/math]. In that case, the function evaluates to [math]\frac{\pi}{(5+0)(2+0)} \delta (0)[/math]

so this function you're given matches exactly the function [math] \frac{\pi}{10} \delta (\omega)[/math] everywhere.

[Anonymous No.9321442]

>>9321422
Ohh, thank you. I guess it's common knowledge but I wish my professor mentioned it in his notes

[Anonymous No.9321449]

>>9321436
yeah, that's what I thought you were doing, that's clearly wrong. the 36 and e^5 need to be under the same radical. I don't use scientific calculators very often but if I recall correctly you should just do your inputs as follows
(1) e^5, (2) +36, (3) sqrt, (4) -6

[Anonymous No.9321453]

>>9321449
It worked appreciated

[Anonymous No.9321673]

>>9320527
>If you haven't learned geometry and analysis yet you are not mathematically mature enough to understand these texts.
Retardedly wrong.

[Anonymous No.9321682]

Could we ever, in the future, drain the gas giants of their outer layers of gas in order to terraform the inner cores?

[Anonymous No.9321684]

Can I ask you one question, where did you get the nerve?

[Anonymous No.9321728]

You know how they give you that "one in every three of you" speech at the start of your first year engineering course? Well what if your buddy was that one of the three and is asking you for career direction advice? What would you say?

[Anonymous No.9321735]

>>9320529
That would actually be correct though.

[Anonymous No.9321748]

>>9321728
>You know how they give you that "one in every three of you" speech at the start of your first year engineering course?
No, since I'm not engineer scum.

[Anonymous No.9321753]

>>9321728
Tell him to sell his boypussy for a living.

[Anonymous No.9321794]

How do final grades work at most universities? So far in one of my classes we've had two midterms and the average on each has been around 50%, which seems really low to me. At this rate I can't imagine half the people would pass the class, but the syllabus didn't include a grading scale for final grades, which my previous university always did.

[Anonymous No.9322028]

>>9321440
hey, quick question. So, what about the 1/2pi outside of the integral? is that also taken into account and the final answer is pi/10 or do you have to multiply it by 1/2pi giving you 1/20 as the final answer.

[Anonymous No.9322049]

Outside of Dark Matter and Exotic Matter (Imaginary/negative mass/etc) are there any unconfirmed particles of the standard model we need to complete the picture that we predict or is it mostly done say for Dark Matter?

[Anonymous No.9322096]

>>9322028
it depends on your definition of the transform, there are variants.

I used a definition where 1 transforms into delta

do you not have a table with usual transforms?

[Anonymous No.9322100]

>>9322028
>>9322096
also please make sure I'm not telling you some stupid things. I haven't used these tools in a very long time so try to verify that it makes sense.

Would love if someone else confirmed.

[Anonymous No.9322243]

>>9322100
Your explanation made sense. I watched a jewtube video where they explain the delta function. Okay what about this one, this is my last. I can't make much of these even when looking at the table desu.

For b, if I make delta(0) then my omega will become -2 right? So I get 10•e^-2t, but the denominator is the confusing part. My friend showed me his solution and he got j on the numerator and I honestly don't know how he did that.

[Anonymous No.9322263]

>>9322243
ok I checked

you can just compute the inverse fourier transform by hand to be honest

I'll give you a simple example and you can work out the rest

remember that by definition of dirac's delta distribution, you get [math] \int_{-\infty}^{+\infty} h(s)\delta(s-a)ds = h(a) [/math] for any test function h.

So if you try to compute the inverse FT of [math]\hat{f}(\omega) = \frac{\delta(\omega)}{1+j\omega}[/math], you get [math]f(t) = \int_{-\infty}^{+\infty} \hat{f}(\omega) e^{2 \pi j t \omega} d\omega[/math]

which is:

[math]\int_{-\infty}^{+\infty} \frac{\delta(\omega)}{1+j\omega} e^{2 \pi j t \omega} d\omega[/math]. From the definition of dirac's delta, this simplifies to: [math] \frac{1}{1+ j\times 0} e^{2 \pi j t \times 0} = 1 [/math]

which is basically what I had told you, but maybe this is a better way to do it if you're following a course.

Now just replace my simple [math]\frac{\delta(\omega)}{1+j\omega} [/math] with whatever example you're given and work it out, it doesn't look too hard

[Anonymous No.9322266]

>>9322049
The graviton hasn't been detected, asuming it even exists.

[Anonymous No.9322286]

>>9321323
This is immediately obvious from a non-set-theoretic point of view.

[Anonymous No.9322292]

>>9322049
graviton/gravitino
tachyon
dyon
glutino
photino
higgsino
neutralino
chargino
axion/axino
sfermion (stop squark)
planck particle
dilaton
dual graviton
leptoquark
majoron
majorana fermion
magnetic monopole
preon
sterile neutrino
W' and Z' bosons
X and Y bosons

as for composites,
hexaquark
skyrmion
glueball
theta meson
t meson
mesonic molecule
pomeron
diquarks

[Anonymous No.9322295]

>>9322049
>Dark Matter and Exotic Matter
They're basically fiction at this point.

[Anonymous No.9322327]

I want to buy a house near mcgill university and rent it out while attending the school. Is this a good idea? will the canadian housing market plummet within 10 years?

[Anonymous No.9322465]

>>9316173
Found this operator notation for the Taylor series expansion, now I'm not a matemathician but I'm doing more "mathematical" work nowadays so before writing a report that screams "ENGINEER" all over I want you guys to answer me: is it correct? Or is it a massive abuse of notation?

[Anonymous No.9322472]

>>9322465
if you're interested in how this works rigorously you can read up on C0 semigroups.
https://en.wikipedia.org/wiki/C0-semigroup
The taylor series approach doesn't work in most cases, since it assumes that f is infinitely often differentiable.
Also there is no good way of knowing if the series converges since, the operator in question is unbounded

[Anonymous No.9322484]

>>9322472
but my functions are analytic, specifically trigonometric functions. So I guess that covers me on both the differentiability and convergence departments?
Reading it nonetheless.

[Anonymous No.9322495]

>>9316974
you mean /x/

[Anonymous No.9322501]

>>9322484
that covers the differentiability, but not the convergence.
Let me give you an example.
We know that the taylor series for [math] e^{At} [/math] converges for [math] n\times n[/math] matrices, because
[math] \left \| e^{At} \right \| \leq \sum_{k=0}^{\infty}\frac{\left \| A \right \|^k}{k!} < \infty[/math]
That doesn't work for any linear operator though.
For example [math] \left \| \frac{\partial }{\partial x} \right \| = \infty [/math] roughly speaking. That's because you can construct sequences of functions that would converge normally, but don't converge once you use the operartor on them.
An example would be [math] f_n(x) = \frac{\sin(n^2x)}{n} [/math] where [math] \lim_n f_n(x) = 0 [/math], but [math] \lim_n \frac{\partial }{\partial x} f_n(x)=\lim_n n\cos(n^2x) [/math] doesn't exist.

[Anonymous No.9322582]

can a gentle soul explain to me how or what is population inversion when it comes to NMR

fucking oldass teacher can't explain for shit

[Anonymous No.9322615]

If I shave my ass and get a cut, is it bad if I take a shit and some shit gets in the cut?

[Anonymous No.9322632]

Is extending human lifespan a complete and utter meme or is it something with substance that could actually be done in our lifetime if we are in our 30s now?

How much of it is a scam and what's the realistic version?

[Anonymous No.9322645]

>>9322632
It's already been extending for hundreds of years retard

[Anonymous No.9322648]

>>9322632
Medical science these days is all about patent drugs and shit.
Life prolonging medication (or some others 'means') first will require massive funding for research, and even then most of it will be spend on high executice salaries.

Also even if it does happen it will probably be secret and only ultra rich will be able to afford it.

Longevity is a fusion of medical science

[Anonymous No.9322650]

>>9322648
>muh ebil gabidalism
see >>9322645

[Anonymous No.9322651]

How do I show that the number of subsets of [math]U = {1, 2, 3, ..., n}[/math] of even cardinality that do not contain 1 is equal to the number of subsets of [math]U[/math] of odd cardinality containing 1?

Also, generally speaking, if I want to show a set has some cardinality using a bijection to another set, are there any rules or tricks on how to create this other set?

>tfw eternal brainlet trying to self learn from discrete math books

[Anonymous No.9322654]

>>9316173

As I am finally going to be able to afford stuff again and one of those things will be college because I'm American haha I am thinking about what I want to go for.

My question is that if I wanted to study stuff in the arctic and things of that nature what would it be best to major in? Really stupid, I know, but I'm going on little sleep right now and don't know any other way to phrase it.

[Anonymous No.9322655]

>>9322648
poor people have had the biggest increase in life expectancy for the last 50 years retard

[Anonymous No.9322668]

>>9322654
geology/biology/climate science are all active in the arctic
I guess just go to the university and ask around the relevant departments, or student counselors.

[Anonymous No.9322669]

>>9322655
We are not talking about natural life span, poor people just have access to better healthcare than 100 years ago and die prematurely less often.
We are talking about extending life, think about living for 150, 200 years and longer (and not being a cripple at the same time)

[Anonymous No.9322679]

>>9322669
>poor people just have access to better healthcare
That IS why people live longer retard. There isn't any "+10 years" pill that anyone is taking.
>die prematurely
prematurely is a relative measure dummy. Even if you're poor, 65 is considered prematurely today, while it was considered natural causes for a rich person 200 years ago.

Again, poor people have benefited more than rich people in the last 50 years. You believe literally the opposite of what is true

[Anonymous No.9322686]

>>9322669
>Medical science these days is all about patent drugs and shit.
>only ultra rich will be able to afford it.
>poor people just have access to better healthcare than 100 years ago
Make up your mind faggot

[Anonymous No.9322688]

>>9321673
Ask yourself if a highschooler can to category theory...

[Anonymous No.9322691]

>>9321728
>"one in every three of you"
We had "2 in every three of you" speech.
Thankfully I am less of a brainlet then the other people and the only friend I have is not a brainlet.
The trick is to not have friends.

[Anonymous No.9322694]

>>9322688
Depends on the highschooler. Claiming that analysis is somehow a prerequisite for it (in any way whatsoever) is truly retarded.

[Anonymous No.9322730]

>>9322679
Where did I say there is such a pill?

>>9322686
All of those statements are correct, if or when treatments that greatly prolong life become a reality general public wont even know about it. Only mega rich will have them.

[Anonymous No.9322737]

>>9316236
Didn't check but I think; NH3 + NaOH -> NH2- + H2O + Na

[Anonymous No.9322739]

>>9322730
>Where did I say there is such a pill?
>>9322648 "Life prolonging medication"
Your entire argument is that life extension will be due to some "secret" invention for rich people. This is factually wrong. "Life prolonging medication" already exists and benefit poor more than rich. You believe literally the opposite of what is true

[Anonymous No.9322743]

EMAG Relativity Question

Hey guys, missed my lectures where the lecturer covered this so going by what I remember from other classes.

Question is pic, I'm thinking I should apply some sort of Lorentz boost to the matrix and somehow the product should be the answers? Anyone wanna help out?

[Anonymous No.9322760]

>>9322730
>if or when treatments that greatly prolong life
>if or when
70 used to be really old, today it's barely retirement age.
>general public wont even know about it. Only mega rich will have them.
>this future speculation goes against all evidence today, but it's true because I said so
lol

[Anonymous No.9322768]

>>9322730
>general public wont even know about it. Only mega rich will have them.
>rich people suddenly starts living 200 years while everyone else dies at 80
>nobody notices and keeps going on about their business
Does this actually make sense to you? Is this really how your brain works?

[Anonymous No.9322770]

>>9322768
That's how your average poltard thinks

[Anonymous No.9322839]

>>9322694
>Claiming that analysis is somehow a prerequisite for it
No I did specifically not claim that. I said that if you likely weren't mathematically mature enough, which just meant that usually you should have a certain breadth of math knowledge before diving deep into a certain topic.

>Depends on the highschooler.
Of course.

[Anonymous No.9322869]

Anyone give me a hand for part ii in Q1? I got the first part easy enough. I thought part ii would be the usual way I do elevator problems but I'm getting the wrong answer. The answer is also in terms of g by the way

[Anonymous No.9322899]

>>9322869
Is it 1+1/12g and 1-1/10g?

[Anonymous No.9322912]

>>9322768
That's essentially how things work already. The average lifespan in Sierra Leone is 50 and in Japan is 84. People in Sierra Leone likely aren't aware how much better it is elsewhere, yet things continue as they are.

[Anonymous No.9322965]

>>9322912
>The average lifespan in Sierra Leone is 50
Which is higher than what it used to be in japan just a few generations ago dummy.
>things continue as they are
Wrong (as stated above several times). The life expectancy in Sierra Leone has almost DOUBLED in 50 years. During the same time Japan's only increased by ~25%, several times less.

[Anonymous No.9322970]

>>9322965
The point was the gap in lifespans, obviously average lifespans generally go up.

[Anonymous No.9322986]

>>9322743
so do you know anything about the electromagnetic tensor? the lorentz transformation tensor?

[Anonymous No.9322988]

>>9322651

say you're given A, a subset of U that has an odd cardinality and that contains 1.

Can you construct another set B that has an even cardinality and doesn't contain 1 by doing something to A?

[Anonymous No.9322989]

>>9322768
>>9322912
It is already like this in the sense that richer people (and countries) can afford better healthcare, not necessarily because they are more "productive" like neolib discourse would like. Thus, even if we do realize only the rich are living decades more than us, people will likely jump out to justify this shit.

[Anonymous No.9322997]

What is the importance of numbers to mathematics?

[Anonymous No.9322999]

>>9322970
>>9322989
>the gap in lifespans
What the fuck do you think happens to the gap when one value grows way faster than the other?
Is this picture retard friendly enough for you?

[Anonymous No.9323004]

>>9322999
create your own topic faggot.

the gap is only closing because japanese people already reached the limits of human lifespan while people in sierra leone don't die at birth as much.

you really are a fucking faggot.

[Anonymous No.9323015]

>>9323004
>japanese people already reached the limits of human lifespan
Make up your mind faggot. Are rich people living longer and longer or not?
>only because people in sierra leone don't die at birth as much.
Median age in SL is increasing too retard.
I'm sorry the world doesn't agree with your ideology.

[Anonymous No.9323017]

>>9323015
I'm not the other person you're responding to. You're just highjacking a thread for no reason.

fuck off, make your own thread.

[Anonymous No.9323022]

>>9323017
>fuck off, make your own thread.
>he says while trying to continue the argument
lol
also stop teenager-spacing your text.

[Anonymous No.9323070]

>>9323022
>>he says while trying to continue the argument
I'm not a "he".

[Anonymous No.9323088]

>>9323070
>complain about something actually related to a question being off topic
>starts arguing about something nobody even asked about
lol

[Anonymous No.9323092]

>>9322295
i wouldn't call it that, dark matter is just a way to describe the way space manages to expand, among other things

dark matter is part of the lambda cdm model, which is far from fiction. despite whatever you believe to be true, dark matter is no more "fiction" than it was a few years ago

exotic matter is just a term for "weird", unknown, or uncommon matter or states of matter. it encompasses dark matter, hypothetical particles, matter at high pressures (since the chemical properties change), states of matter like bose-einstein condensate, rydberg matter (and another one that i'm forgetting), and exotic atoms which are just atoms that chemists fuck with by, for instance, replacing an electron with a muon just for kicks (exotic atoms are incredibly unstable, which is why they're exotic in the first place)

[Anonymous No.9323097]

>>9323092
>dark matter is just a way to describe the way space manages to expand
That's dark energy lol.

[Anonymous No.9323103]

>>9323092
>hypothetical particles
So in other words fiction? Got it.

[Anonymous No.9323116]

>>9323097
yup, you're right, i confuse those often
dark matter are particles that try to explain gravitational lens (weak lensing), formation of galaxies, and something to do with the cosmic microwave background

>>9323103
higgs boson was hypothetical too, until it wasn't
plus exotic matter is just a broad term that encompasses hypothetical particles, but most of the items i listed for exotic matter have been observed before

[Anonymous No.9323154]

>>9322986
No & Kind of

[Anonymous No.9323179]

I need an operation that I can use in excel to give an output of -1 (for negative numbers), 1 (for positive numbers), or 0 (for 0). How can I do it?

[Anonymous No.9323185]

>>9323116
>higgs boson was hypothetical too, until it wasn't

It's not real and it never has been.

They even wear hard hats at CERN for God's sake, as if these non-physical particles are going to fall out and hit them on the head. It's actually quite hilarious.

[Anonymous No.9323191]

Probably im fucking stupid, but if you define cv as a partial derivative of u=u(t,v), why can you describe it both as a function of (t,p) and (t,v) and not only as the latter?

Also this doesn't make sense to me because for simple compressible substances you can't express u as u=u(p,t) as this two variables can be dependent, or can you?

[Anonymous No.9323201]

>>9323179
=SIGN(number)

[Anonymous No.9323220]

>>9323191
Thermodynamics is the symplectic geometry of the phase space with theormodynamical variables. Given a pair of canonical variables (P and V, say), through a suitable Legendre transformation dynamical quantities such as the heat capacity can be expressed in another pair of conincal variables (S and T, say).
Start here: https://arxiv.org/abs/1111.5056

[stein No.9323228]

>>9323220
not that guy, but I wish this is how thermodynamics was introduced to everyone.

it would have made things so much clearer holy shit

[Anonymous No.9323526]

>>9323201
Danke schön!

[Anonymous No.9323560]

is it enough to study physics basics using "university
physics" book ? or should i start with the feynmen lectures?

[Anonymous No.9323600]

>>9323560
Starting with Feynmann lecture notes is surely a meme

[Anonymous No.9323736]

Does anyone have an idea why GFP instead of aequorin was adopted for protein tagging? Is it just because GFP was engineered for this usage first?

[Anonymous No.9323769]

I took courses up to Differential equations. The problem I have now is that I can't recall some shit from math in General. Do you guys start from the ground up or do you just re start at the last course you took? Serious question.

[Anonymous No.9323776]

>>9323769
i look up things on the fly as i need them

[Anonymous No.9323833]

>>9323220
the only thing i don't understand in this post is Legendre transformation
could you go over that real quick?

[Anonymous No.9323854]

>>9316173
How can Kinetic Energy define energy due to the motion of an object if an object's perceived motion is entirely relative? Is Kinetic Energy simply another measure for potential energy?

[Anonymous No.9323861]

>>9323854
what?
yes it's relative but we just work in a single frame of reference for the sake of ease, but it is possible to convert to other frames of reference as well

not sure where you got the KE=PE idea from though

[Anonymous No.9323895]

>>9323861
PE as in the amount of energy needed to accelerate an object to a specific velocity, such that PE is now equal to KE from the stationary reference point from which it accelerated. Am I wrong?

[Anonymous No.9323906]

Quick, why am I getting the Fourier transform for the sinc(t) cutting off at 0,5 when it should be at 1?

[Anonymous No.9323910]

>>9323895
Potential energy is the energy a body currently has due to its position in a force field. The total mechanical energy is the sum of the potential energy and the kinetic energy, they're complementary.

[Anonymous No.9323914]

>>9323895
well yes, if you go to the frame of reference of a moving object, PE and KE switch places

that doesn't make them equivalent, that just rewords the problem

[Anonymous No.9323918]

>>9323906
i was going to give a quick answer to this problem but since you demanded it to be quick i'll answer it in an hour

[Anonymous No.9323939]

>>9323918
It's because the thread is ending soon, and every time I post questions with over 300 replies on, I never get answered.

[Anonymous No.9323974]

>>9323769
Google the stuff you are not sure about.
If you didn't properly learn things, it's better to read an entire textbook; especially for basic stuff like calculus and linear algebra.

[Anonymous No.9323978]

>>9323939
i think you mixed t up with w

[Anonymous No.9324002]

I'm aware of the proof of the sum of normal distributions using the convolution theorem. But it's super complicated because its for the general case. How do I find the simple solution for the case of mean = 0 and var = some constant?

[Anonymous No.9324008]

How do I parameterize the path C for the line integral?

[Anonymous No.9324009]

>>9323978
Sorry, I don't follow.

[Anonymous No.9324011]

>>9324002
Use their moment generating functions, or their characteristic functions.

[Anonymous No.9324016]

>>9324008
https://www.google.com/search?q=cone+parameterization

[Anonymous No.9324022]

>>9324016
we never learned how to parameterize surfaces

[Anonymous No.9324026]

>>9324011

We haven't 'learned' either of those

[Anonymous No.9324031]

>>9324022
x and y are the circle with radius r, so we just have
x=rcos(theta)
y=rsin(theta)
and then z is dependent on r as well, so we just have
z=r

[Anonymous No.9324039]

>>9324026
Then use the convolution.

>>9324022
Think what z=sqrt(x^2+y^2) means.
It means that as you go through the plane, the z coordinate is equal to the length of (x,y).
You can describe (x,y) as r(cosθ,sinθ), where r is the length of (x,y) and (cosθ,sinθ) is its (unit) direction (θ is the angle).
Then, z can be described by r.
Therefore you can can describe the points [math] (x,y,z): x \in \mathbb{R} \land y \in \mathbb{R} \land z=\sqrt{x^2+y^2}
[/math] as the points [math] (r\cos\theta,r\sin\theta,r) ; r \in \mathbb{R} \land \theta \in [0,2\pi) [/math] .

[Anonymous No.9324041]

[Anonymous No.9324054]

>>9324039

https://en.wikipedia.org/wiki/Sum_of_normally_distributed_random_variables#Proof_using_convolutions

...is this really the only way? I'm going to cry

[Anonymous No.9324060]

>>9324031
>>9324039
no, I got it, it's just that we were never taught this in class so I was dumbfounded.

[Anonymous No.9324072]

>>9324060
read up on cylindrical and spherical coordinate systems and you'll have the tools necessary to tackle most problems

otherwise you could just make up your own coordinate system or transformation and just use the jacobian matrix, but you likely won't need to do this

[Anonymous No.9324081]

is the bottom the negation of the top? or did i fuck up.

[Anonymous No.9324082]

>>9324054
The integral is much simpler because their means are both zero and their variances are equal.

[Anonymous No.9324090]

>>9324072
this is calc 3 dude, I have no idea what a jacobin is and I'd probably get marked 0 on an exam for using it. I know about cylindrical and spherical coordinates though, I don't know why it didn't click sooner.

[Anonymous No.9324094]

>>9324060
You probably missed it or something.
How did you do Stokes theorem which involves surfaces integrals which you calculate by parametrizing surfaces?

[Anonymous No.9324109]

>>9324090
i took calc 3 in high school and we covered jacobian matricies, and i took calc 3 in college and we covered jacobian matricies

we didn't go over exactly why it works, that's beyond calc 3 material, but we just used it to transform coordinates (e.g. treat an ellipse like a circle by adding an extra term that "squishes" the ellipse)

if your class hasn't covered it, then you won't really need to worry about it for a while

>>9324094
F*dS -> F*r dr -> F(r(t))*r(t) dt (by stokes theorem) where r is the function we just parameterized

[Anonymous No.9324128]

>>9324109

[Anonymous No.9324157]

>>9324128
never liked axlers wording
he uses words where he should use symbols, and here you can see plain out redundancy, "on the set sigma(gamma)" that just makes it sound more confusing

either way this still scopes past calc 3 material, which is why this is in a linear algebra book

[Anonymous No.9324163]

>>9324157
>either way this still scopes past calc 3 material, which is why this is in a linear algebra book
No it doesn't.
Calculus 3 Requires linear algebra. It's not past calc 3 material. It is pre calc 3 material.

[Anonymous No.9324418]

exactly what is the muscular structure of an octopus tentacle like?

[Anonymous No.9324439]

>>9324418
>inb4 blue board

[Anonymous No.9324655]

if i lose my finger, would the doctor be able to reattach it?

[Anonymous No.9324719]

>>9324655
it depends on the state of necrosis, where the muscles were cut, etc.

ice tends to slow down necrosis which is why you see that in movies or tv shows