/sci/ - Science & Math

Can someone explain to me why a p series with p = 1.000001 will converge but a p series with p = 1 won't?

>>9256446

The latter divergeth by comparison with the series
1 + 1/2 + 1/4 + 1/4 + 1/8 + 1/8 + 1/8 + 1/8 + &c. This is Cauchy's condensation test; alternatively, it divergeth by comparison with the corresponding integral which is log x.

The former converges by the use of Cauchy's condensation test since it then becomes a convergent geometric series. Alternatively, it converges by comparison with the corresponding integral.

>>9256466
>divergeth

>>9256472
>which'd've divergeth'd

>>9256472
he has a lisp

Why is there so much pepe posting on /sci/? Does /sci/ really love it that much?

How do I rearrange this equation in terms of B?
The best I can do is (+/-)B = D(A/100)+C, but I have no idea what sign B actually has. How do I know which one is the right one?

>>9256526
>How do I know which one is the right one?
You don't, there's two solutions.

>>9256554
That's what I was afraid of.
How do you resolve this kind of thing programmatically? I need to reverse-engineer a calculation I did that makes liberal use of absolute values, but it seems like the mathematical arrow only points one direction here.

>>9256572
>How do you resolve this kind of thing programmatically?
Depends on the specific context.

through what media are gravitational waves conveyed?
Light is electromagnetic
sound uses the air
conventional waves use fluid
so what does gravity use?

>>9256578
>through what media are gravitational waves conveyed?
God particles

Are there different types of ribosomes?

>>9256575
True, true.
I just did the legwork and refactored the original calculations to either circumvent absolute values or record signs where possible, and it's working smoothly.
I thought I could be lazy by applying some math, but math has no patience for that kind of shit I guess.

anyone have a source for that article that gets posted here frequently on how colleges are teaching lower and lower level math?

>>9256335
Here's a proof that my brainlet brain is having trouble with.

Let [math]P[/math] be the powerset of the natural numbers. Suppose that there's a function [math]f: \mathbb{N} \to P [/math] that enumerates [math]P[/math] (in other words, a surjective function) and consider the set [math]D = \{n : n \notin f(n) \}[/math]. [math]D \in P[/math] because [math]D[/math] is a subset of the naturals. So there's some [math]d[/math] such that [math]f(d) = D[/math]. - This is the part that I don't understand - So we have, for all numbers n, [math]n \in f(d)[/math] iff [math]n \notin f(n)[/math]. Hence in particular [math]d \in f(d)[/math] iff [math]d \notin f(d)[/math]. Contradiction.

Okay I get the logic and it's hard to pinpoint exactly where I have issues with the proof but I think essentially my issue is can we really just assume that there's a diagonal set like that? It feels to me that the way we defined the diagonal set is what's contradictory in nature, not the final conclusion which is just a result of an incoherent or senseless set that we built. I know however that the theorem is true because I'm seen more straightforward and imo better worded proofs of it. Thoughts and maybe can I get a sharper equivalent proof?

>>9256578
Light does not use a medium.
Gravitational waves are oscillations of space time itself.

>>9256633
What exactly is the issue you have with the diagonal set? f maps naturals to subsets of naturals, and either the natural is mapped to a set containing it or it isn't.

>>9256646
Like I said it's hard to pinpoint exactly my issue, I'll tell you what I'd conclude this proof with instead and maybe you'll be able to tell better what I'm confused about

"There's no Diagonal set" because by hypothesis there is no subset of N that isn't enumerated by f(n) and the diagonal set is a subset of N.

>>9256674
>"There's no Diagonal set" because by hypothesis there is no subset of N that isn't enumerated by f(n) and the diagonal set is a subset of N.
This conclusion doesn't make any sense to me, the hypothesis that P is enumerable doesn't tell you anything about which naturals don't get sent to subsets containing them. Can you add more steps to explain how you come to this conclusion?

The argument is just:
Assume you have enumeration f
Consider the set D (you don't make any assumptions about D)
Since f was an enumeration there is some d mapping to D, so f(d)=D
If d is in D, then d is not in f(d)=D (by definition of D), a contradiction.
If d is not in D, then d is in f(d)=D (by definition of D), a contradiction.
Those are the only two possible cases, so the only assumption that was made must be false, i.e. P is not enumerable

Does anyone have a pdf of the answer book/instructors book for "Tutorials in Introductory Physics Homework" by McDermott? Or at least point me where to find it?

>>9256694
Nvm, got it now. Thanks man

how the fuck can a bunch of wires show us things like tv, games, movies, etc? it just blows my mind. i mean they are metal wires and materials in the ground and yet they are capable of doing stuff like that.

Say I had a machine that could create a gravitational singularity with infinite density. If I then moved that machine, and so moved the singularity, through space would I be opposed in the same way as I would be just moving the machinery or does the singularity have conventional inertia in the same way a conventional mass would?

>>9256903
>infinite density

>>9256645
I was under the impression that electromagnetic waves were themselves the medium, as they're just two waves bouncing off each other at right angles or something

What is love /sci/?

text says to calculate the rank of this matrix and it says that the answer is 3
but if I add the 2nd row to the 1st row and then subtract twice the 3rd row from the 1st row, I get a row of 0s, so the rank would be 2?
I understand it depends if the rows/columns are vectors but it literally doesn't say if it's a row or column matrix

>>9256952
OK I realized I made a retarded mistake, nevermind

>>9256903
>Say I had a machine that could create a gravitational singularity with infinite density. If I then moved that machine, and so moved the singularity, through space would I be opposed in the same way as I would be just moving the machinery or does the singularity have conventional inertia in the same way a conventional mass would?
Physics breaks down at a singularity, so no one can say whether infinite smallness or infinite density are even meaningful terms in regard to one. But total mass is all that would affect its inertia, not the density of the mass. You could theoretically squeeze a grain of sand to a density at which it would become a tiny black hole, but it would still have the mass and related properties of a grain of sand.

How do i get an arbitrarily high moment from a moment generating function without having to actually take the derivatives? Like in the third question my prof gets the 12th moment through some observation of a property of the mgf that I dont understand. I can do the first and second questions by taking the first and second derivative of the mgf. Am i just supposed to recognize a pattern or is there some general trick to this?

>>9256997
look at https://en.wikipedia.org/wiki/Moment-generating_function#Definition where you have
M_X(t) =
sum_{k=0}^\infty (t^k m_k)/k!
where m_k is the kth moment

so if
M_X(t) =
e^(3t^2)

then
M_X(t) =
sum_{k=0}^\infty (3t^2)^k / k!
[taylor expansion of e^(3t^2)]

so to find m_{12} you just match up the coefficient of t^12 as done in your image, in the taylor expansion you look at when k=6 since that gives you
3^6 t^{12} / 6!
and in the moment generating function expansion you look at k=12 since that gives you
t^{12} m_{12} / 12!
then solve for m_{12}

>>9256335
So, I'm trying to figure out a possible way to make liquid air in my back yard.

My idea so far:
>compress to as high a pressure as practically possible; a few thousand psi, maybe more if it can be done safely
>cool to around -40C using a modified aircon system
>expand this cool, compressed gas through a needle valve into an insulated vacuum chamber

Will the rapid expansion cause the gas to cool enough to liquefy? I know enough about air conditioning systems to make what I have in mind work, but I don't know if the science behind it is solid.

>>9256480
kekth'd

how do I find riemann normal coordinates around an arbitrary event?

>>9256526
First remember that if X >= 0, then |X| = X
and if X < 0, then |X| = -X
Rearrange your equation to get
0.001*AD = |B - C|
Then there are two cases:
If B - C >= 0, then 0.001*AD = B - C
which means that B = C + 0.001AD
Otherwise, if B - C < 0, then 0.001*AD = C - B
which means that B = C - 0.001*AD

Stats brainlet here, I feel like I must be completely misunderstanding the method of moments because I'm getting an unbiased estimator that should be biased according to the exercise (and considering the circular nature of my calculations I'm not surprised that it seems to be unbiased). Could someone point out what I'm doing wrong?

How come sometimes you have to pee really bad, but when you finally do there's a lot less than you expected?

>>9257647
That is some autistic writing, are those squares either those squares are 1x1cm or you can't write for shit.

Why do people write math on grid paper anyway?

>>9257663
The squares are exactly 1x1cm, yes. How does their size make the writing more or less autistic?

Hello.

"Given the region bounded by [math]y = x^{2}[/math] and [math]y = 1 [/math], find the volume given by a partial rotation with angle [math]\theta[/math] around x-axis".

I don't know how what the fuck I'm supposed to do now.
pls halp

>>9256633
>>9256633
The existence of set D follows from
https://en.wikipedia.org/wiki/Axiom_schema_of_specification

Which, in essence, says that if you have a way of assign a sentence to each element of a set A, then there exists a subset B composed of all elements for which the sentence corresponding to that element is true. In your case the sentence assigned to n is "n is not an element of f(n)".

>>9257668
Because it'd look more æstetic if you sized your writing accordingly to fill the entire square instead of leaving it half empty vertically, like this:

(also pls dont dox me)

>>9257682
I like leaving some space so I can fit taller symbols/formulas without having to either squish them down or skip entire lines.

>also pls dont dox me
maybe you shouldn't bully people on the internet

>>9257673
i would use a double integral in polar coordinates

>>9257709
I still don't know this stuff

>>9257518
https://en.wikipedia.org/wiki/Normal_coordinates#Geodesic_normal_coordinates

What's a good textbook / lecture notes to get started in tensor analysis?

Target
>brainlet electrical engineer
>already graduated so my formal "mathematical proof" skills are pretty rusted

Goals
>get an intuitive understanding about the difference between tensors and matrices
>get enough intuition so I can use this tool
>eventually understand why it's so important on the general relatively (beside ease of notation)
>if possible a book with a lot of examples / detailed exercises answers

Why is Lim h->0 (f(g(x+h))-f(g(x)))/(g(x+h)-g(x))=f'(g(x))?

>>9257726
Why would you try to find volumes which require double integrals in polar coordinates before learning about double integrals and polar coordinates?

What is a better way to understand Catalan numbers?

Not sure how this cipher is supposed to work. How am I supposed to get 1005036864 from 'E' XOR h? Using Python.

>>9258012

>>9257928
Both [math]f[/math] and [math]g[/math] need to be continuous and if the derivate of [math]f[/math] exists at [math]g(x)[/math], then it is because [math]g(x+h)[/math] approaches [math]g(x)[/math] if [math]h\to 0[/math], so you could substitute [math]g(x+h)[/math] by [math]y[/math] and [math]g(x)[/math] by [math]a[/math] and then you get [math]\lim_{y\to a}\frac{f(y)-f(a)}{y-a}=f'{a}[/math] by the definition.

>>9258071
[math]\lim_{y\to a}\frac{f(y)-f(a)}{y-a}=f'{a}[/math] written again

>>9258075
[math]\lim_{y\to a} \frac{f(y)-f(a)}{y-a} =f'(a)[/math] written correctly

How can I evaluate this integral?
[math]\int \sqrt{x^{2}+25} dx [/math]

I did the trig substitution but I got stuck at [math]25 \int sec^3{\theta} d \theta [/math]

Say I have [math]\int_0^\infty \frac{\sqrt{x}}{x^2+1}dx [/math]
I can solve this by going to the complex plane then the integral needs to be from minus infinity

[math]\int_0^\infty \frac{\sqrt{x}}{x^2+1}dx = \frac{1}{1+i}\int_{-\infty}^\infty \frac{\sqrt{x}}{x^2+1}dx [/math]

I do not see where that [math]\frac{1}{1+i}[/math] comes from.

I guess it's like the half you get when you extend an even function in this way but I just don't see how.

>>9258153
>Say I have [math]\int_0^\infty \frac{\sqrt{x}}{x^2+1}dx[/math]
>[math]\int_0^\infty[/math]
>[math]\infty[/math]
No you don't.

>>9258153
>I do not see where that 11+i comes from.
Then why do you think the equality is true?

>>9258153
int_{-\infty}^\infty \frac{sqrt{x}}{x^2+1}dx =
int_{-\infty}^0 \frac{sqrt{x}}{x^2+1}dx + int_0^\infty \frac{sqrt{x}}{x^2+1}dx =
-int_\infty^0 \frac{sqrt{-x}}{(-x)^2+1}dx + int_0^\infty \frac{sqrt{x}}{x^2+1}dx =
-int_\infty^0 \frac{i*sqrt{x}}{x^2+1}dx + int_0^\infty \frac{sqrt{x}}{x^2+1}dx =
int_0^\infty \frac{i*sqrt{x}}{x^2+1}dx + int_0^\infty \frac{sqrt{x}}{x^2+1}dx =
i*int_0^\infty \frac{sqrt{x}}{x^2+1}dx + int_0^\infty \frac{sqrt{x}}{x^2+1}dx =
(1+i)*int_0^\infty \frac{sqrt{x}}{x^2+1}dx

>>9258152
pls halp

>>9258152
>>9258252
http://tutorial.math.lamar.edu/Classes/CalcII/TrigSubstitutions.aspx

>>9258219
I saw it in a calculation that did not explain it, it was just another step.
>>9258242
Thank you!

i just bombed 3 exams, 2 of them in courses that are prerequisites for next semester. should i drop them and waste a year, or should i take a gamble on the final exam

Is there any similarity between the concepts of a unit root for a time series dataset, and the characteristic roots of a function?

Or are they just similar in name? They both have something to do with differential equations I think, right?

Whats the best place to learn about phasors?

My professor butchered the explanation for them and I've been left wondering what the fuck I just read.

>>9257950
idk visit Catalan?

Is the word "scientist" protected in any way?
If i get a Bachelor's degree in Computer Science, can i call myself a scientist?

>>9258397
>If i get a Bachelor's degree in Computer Science, can i call myself a scientist?
No, computer science doesn't use the scientific method.

>>9258397
>>9258413

No, just look at (((Bill Nye))) the (((Science))) Guy

>>9258413
Which makes it superior.

>>9258421
He's called the science guy because he explains science. That doesn't make him a scientist. It's like how you might call someone from the IT department of a company "the computer guy" even if he has no degree in computers

>>9258397
The real question is why would you want to?

>>9258479
I want to cosplay as Makise Kurisu from Steins;Gate (she sometimes wears a scientist costume)

My book's definition of perfect set:
closed and doesn't contain isolated points

Wikipedia's definition of perfect set:
S = closure of S

What the fuuuck {1 / n where n is natural} union {0} is closed by wikipedia's definition but that has isolated points up the ass

>>9258487
>n is natural
Arbitrary natural numbers need not be well-defined.

RF/Analog/Mixed signal design or photonics/optoelectronics for EE specialization if I dont plan to stay in academia after grad school? Interested in both options just need to decide on which is best for industry employment.

>>9258510
aRbiTrary NaTuRAl NuMbErs NEed NoT bE WelL DeFINeD

>>9258519
>>>/facebook/

>>9258487
Nvm I was being gay. Wikipedia says
S = limit points of S
not closure of S

How answer Q13?

The formula I have for the variance of a random variable is:
[math]V(X) = E(X^{2}) - E(X)^{2}[/math]

but I don't think I'm doing it correctly.

Essentially the vales I have are:
0*(1/3)
1*(2/9)
2*(4/27)
3*(8/27)

so what should the variance be, assuming X is the left-hand side of those numbers?

>>9258533
Whoops forgot image

>>9258538
What is X?

>>9258547
X is the probability that an email system will correctly classify an email as spam
P(correctly classify) = 2/3
P(Incorrect classify) = 1/3

>>9258539
babby's first algebra based physics class?

I thought this was the stupid questions board?

>>9258538
Pr(X=0) should be 1/27 and Pr(X=2) should be 4/9.

Var(X) should equal 2/3

Need:
The intersection of a perfect set and a compact set that is not compact.

Or need to explain why that's impossible

>>9257327
Well, after a bit of research, it turns out that I basically described an over-complicated version of the Linde process. This should be easier than I thought.

>>9257663
>autistic writing
>Because it'd look more æstetic if you sized your writing accordingly
now here's a pot calling the kettle black if I ever did see one

>>9258533
>>9258539
[math] s=\sqrt{2\cdot9.8\cdot(4\cdot s)}\cdot1+\frac{1}{2}\cdot9.8\cdot1^2 [/math]

>>9258578
>algebra based physics class
I wish I could turn back time
to the good old days

How to lick own butthole

>>9258605
I forgot to include all the details, my bad.
The system is given 3 emails to classify maximum. If it makes one wrong classification, it stops.
So the sample space I got was:
{W, RW, RRW, RRR}
Assuming W = Wrong classification and R = correct classification, and that
P(W) = 1/3
P(R) = 2/3

Or does that not change anything?

Can anyone spoonfeed on the implications of quantum wavefunction collapse?

From what I understand the consensus is that this implies pure randomness and a stochastic universe, but wouldn't it make more sense to assume that the collapse is driven by a deterministic mechanism we can't observe? Can't there be some hidden law or information that determines where the wave will collapse?

If i have two natural numbers and show that their multiple is natural by an axiom of closure of multiplication, and then expand it to a sum of 3 terms, can i conclude that ive proven thwt one of those terms is a natural number by closure of addition?

>>9258681
It's a dichotomy. You can have a deterministic universe, but then it is non-local. We choose the local, non-deterministic interpretation.

>>9258726
More here: https://en.wikipedia.org/wiki/Bell%27s_theorem

>>9258726
>>9258728
Can you perhaps give me a tl;dr of what's the difference between a local and non-local variable?

am i a brainlet? i can't see how this works. i don't see a way to get bd-ac as an element of the natural numbers. i keep getting bd+ac instead.i tried to do some distribution but it didn't help.

>>9257327
Fuck me I know which doujinshi this is from.

>>9258737
Local: respects the speed of light and is Lorentz invariant.

>>9258749
Since they are all greater than zero
[math]0<a<b \\ 0<ac<bc \quad (c>0) \\ 0<c\leq d \\0<cb\leq bd \quad(b>0)\\0<ac<bc=cb\leq bd [/math]

>>9258800
thx bruh

How do i get latex to display on /sci/? is it a browser addon or some plugin?

>>9258886
Check the sticky.

>>9258668
Sorry for the late response.
Your original values are correct then.
Var(X) should equal 56/27 or roughly 2.074.

How accurate is DNA replication?

As in, barring any sort of interference caused by an outside factor, if a strand of DNA replicated itself how accurate would it be? 100%?

>>9258152
Use IBP, u=sec^3(x)dx and dv=1 and then IBP a second time to integrate your original v*du

Anyone know of a 'simple' enumeration for the free magma generated by the natural numbers?

Ideally the 'simple' function would be primitive recursive, but I'll take whatever I can get.

what force mediates the collision of uncharged particles? they do work on each other, but it's not electromagnetic force. is there a word for this? kinetic energy is potential for this, so is the interaction itself 'kinetic force' or something?

>>9259012
100% would mean effectively no mutations. It's one error every 10 billion pb.

>>9256930
>he thinks E- and H-fields are always perpendicular
cute

Let [math](x_{n})[/math] be a convergent sequence and suppose [math]\lim x_{n} [/math] is positive. Show that there exists [math]N \in \mathbb{N}[/math] such that [math]x_{n}>0[/math] for all [math]n>N[/math].

I feel like a contradiction would work. Suppose not, then we have the sequence being positive implies for all [math]N\in \mathbb{N}[/math] there exists [math]n\geq N[/math] such that [math]x_{n} \leq 0 [/math] How do I proceed from here?

>>9259498
You know that [math]L = \lim_{n \to \infty}x_n[/math] is a positive number. What happens when you take [math]\epsilon = \frac{L}{2}[/math] and use the definition of limit?.

>>9256335
How can I get into Maths and physics without going to college/university?

>>9259570

You can't. Spooks will give you a visit at night if you even dare try to self study math/physics.

>>9259498
[math] L:=\lim_{n\to\infty} x_n [/math]
[math] \forall \varepsilon : 0< \varepsilon < L \exists N\in\mathbb{N} : \forall n>N: |x_n-L|<\varepsilon [/math]
[math] |x_n-L|<\varepsilon \implies 0<L-\varepsilon < x_n < L+ \varepsilon [/math]

Is medicine actually hard or what? I've looked over some of the prior exams for a lot of the med subjects at my college and they seem to be really basic rote learning answers. You don't seem to have to make any big inferences, just spit out information you already know. I've taken a few units that the pre-med students do and they seem a lot harder than the actual medicine units. People seem to circlejerk about how hard it is and how they study for 12 hours a day, but from what I can tell the only really bad parts after premed is the internship and dealing with superiors, god complex students etc.

>>9259577
Let's say Spooks and I are in good terms. How do I do it?
Right now and in the short foreseeable future I'm not able to attend college, nor to pay for it.

[math](3!) / ((3-2)!) * 2! = 12[/math]
Wrong but
[math]3! / (2!*(3-2)!) = 3[/math
Correct.

What?

Any hints on this, please?
Evaluate the integral of[math]f(z)=\frac{e^{iz}}{z^2}[/math] over the path [math]\gamma (t) = e^{it}[/math] such that [math]0\leq t \leq 2\pi[/math]

Let L(V)=L (V,V) be all linear maps from V to themselves.

i)dim (L)=?

choose dim (V)=n->dim (L)=n^2

ii)define L(L (V)) in words. Prove it is a vector space

L (L (V))=L (L (V,V),L (V,V)) so it is all linear maps which map all linear maps from V to V...not sure doesn't seem clear

How to prove it is a vector space? There are the 8 requirements i.e. x+y=y+x and so on. How would I even go about doing this? Since I don't even really know what L (L (V)) looks like. Not even sure how I would prove it for L (V)

iii)dim (L (L (V))=?

dim (L(V))=n^2->dim (L (L (V))=n^4

iv)give an example basis of L (L (V))

I'm thinking all n^4×n^4 matrices where i,j=1 all else 0

>>9259779
>Any hints on this, please?
https://en.wikipedia.org/wiki/Residue_theorem

>>9259783
either you're lying when you claim you know dim(L(V)) = n^2 or you should know how to prove L(V) is a vector space. do that first, make sure you understand both. the rest should follow

>>9259815
Yeah, I was trying the hardest way possible. Thanks, man.

>>9259825
I'm sorry, but I don't. I can't quite comprehend L (V). I think of V as a nx1 vector and so for L:V->V means L must be an nxn matrix.

>>9259481
Wouldn't they most often be incidental along a torus shape, rather than a cube?

>>9259825
>>9259854
Nevermind. I realized it is simply all M (n^2xn^2) which is a vector space. Thanks for the (you).

>>9256938
Literally a chemical reaction brought on by the appearance, actions and familiarity with a certain person and/or thing.

The same thing that makes you love a woman is the same thing that makes you love heroin or playing basketball or 4chan. Granted, personal relationships jave a bit more depth and therefore move "value", but the core principle is the same: your brain is releasing neurotransmitter chemicals and making your neurons go pop.

>>9258303
Gamble, if you fail you'll be taking them anyways next year.
>but muh FF
Stop being a failfull faggot

>>9259927
This. I don't get it why people give up. If you get fucked, nothing changes. You were fucked anyways...

>>9259927
thanks for the perspective
but what's FF?

Why?

>>9259973
There's nothing you can do to change it. Deal with it.

>>9259927
>faggot
Why the homophobia?

will the universe eventually implodes due to gravity accumulating more mass which eventually will attract every single matter in the universe?

>>9260067
quit shitposting

>>9260125
>quit shitposting
Quit being homophobic.

I have this paper to read and

>Data are presented as means +- SEM. Differences were considered significant at p < 0.05, as determined by using Student’s paired or unpaired t test (when measures were normally distributed) or Wilcoxon matched-pair or Mann–Whitney U test (when distributions were not normal).

How did they determine wether the distributions were normal or not in the first place? How is this done? I heard once you don't even need a statistical test for that.

>>9260133
quit being a thick-skinned faggot cunt, and fuck off if you can't into board culture

>>9260067
>>9260133
Fuck off to >>>/r/eddit/

>>9260145
>quit being a thick-skinned faggot cunt, and fuck off if you can't into board culture
Homophobia is not a part of any "board culture", and there's certainly nothing scientific or mathematical about it.

>>9260133
Fags are subhuman though, why would I not despise them?

9260067
9260133
9260151
Lurk before posting.

>>9260154
>Fags are subhuman
[citation needed]

>>9260151
why don't you just fuck off back to tumblr and stop pretending to browse 4chan, you digusting flaming faggot?

>>9260159
Don't reply, just report the faggot.

>>9260159
>why don't you just fuck off back to tumblr and stop pretending to browse 4chan, you digusting flaming faggot?
How could I be pretending if I'm here replying to you?

>>9260167
you don't belong here, you belong in a trash can, and as long as you keep yelling at everyone and reminding them how out of place you are, someone will keep telling you to fuck off and off yourself

faggot

>>9260180
>you don't belong here
Why not?

>as long as you keep yelling at everyone
Huh?

>>9260159
You DO know that /lgbt/ is a board right?

Great job ironically exposing your newness.

>>9260188
you are so tremendously flagrant in your idiocy that I'll spell it out for you

no one here has anything against people being gay. calling people faggots in good nature is 4chan culture, and it won't change. asking something as retarded as
>Why the homophobia?
when someone's using faggot in this context instantly outs you as someone who doens't belong here

the kind of stuck up, egotistical, self-righteous faggot who would post this kind of shit, and then follow up with something as tremendously idiotic as
>hurr /lgbt/ is a board i got u, u new hurr
is something nobody here wants around

so once again, fuck off back to plebbit or tumblr or wherever the fuck you came from

>>9260199
>asking something as retarded as
>>Why the homophobia?
>when someone's using faggot in this context instantly outs you as someone who doens't belong here
Wrong.

Using homophobic slurs instantly outs you as someone who doesn't belong here

>>9260204
yeah calling people faggots definitely makes me seem out of place in 4chan huh

fucking imbecile faggot, kill yourself

>>9260204
this is coming from a gay person

kill yourself fag, nobody likes u.

>>9260207
>this is coming from a gay person
>kill yourself fag, nobody likes u.
Real gay people don't use homophobic slurs.

Next?

[math]\color{red}{\textsf{STOP REPLYING TO THE FAGGOT FOR FUCKS SAKE}}[/math]

>>9259498
[math]\lim x_n>0[/math] means that for any [math]\epsilon>0[/math] there exists an [math]N\in\mathbf{N}[/math] such that [math]|x_n-\ell|<\epsilon[/math]. Equivalently, [math]-\epsilon<x_n-\ell<\epsilon[/math] and
[math]\ell-\epsilon<x_n<\epsilon+\ell[/math].
Now what value of epsilon will make the LHS>0? (there's no unique answer)

>>9260206
>yeah calling people faggots definitely makes me seem out of place in 4chan huh
It's a telltale sign that you're underage, and hence don't belong here.

>fucking imbecile faggot, kill yourself
Boring ad hominem.

Next?

[math]\huge\color{RED}{{\textsf{WILL YOU GUYS SHUT THE FUCK UP, I'M TRYING TO STUDY HERE!!!}}}[/math]

>>9260221
>WILL YOU GUYS SHUT THE FUCK UP, I'M TRYING TO STUDY HERE!!!
If he/she would stop abusing homophobic slurs, there wouldn't be a need to correct him/her.

>>9260235
fag

>>9260236
>fag
>>>/b/

>>9260235
Shut the fuck up, faggot cunt nigger bitch.

>>9260238
fag >>>/tumblr/

>>9260235
>he/she
Kill yourself holy shit.

>>9260252
>>9260244
>>9260241
What's wrong with you?

>>9260258
>wAAAAAHHHHHHHHHH
fag
>>>/heliumbag/

>>9260154
>Fags are subhuman though, why would I not despise them?
Luckily, your entitled little shit of an opinion is only worth for people who have to tolerate your bullshit, like your mom and dad.

>>9260281
Yeah? Well your mom's a faggot!

>>9259779
Someone please help me on this again. I can't use the Residue Theorem. I think my professor wants me to solve this way or use some other theorem which I don't recall what is:
[math]\int_{\gamma}f(z)dz = \int_{a}^{b}f(\gamma(t))* \gamma '(t)dt[/math]
I tried doing like this one, but it didn't work well...

>>9260292
>I tried doing like this one, but it didn't work well...
What did you get?

It should work fine.

>>9260296
I got a really weird number (I probably screwed up somewhere) and on wolfram alpha the answer was different.
Still, is there an easier way without the Residue Theorem?

>>9260311
>Still, is there an easier way without the Residue Theorem?
Use the parametrization you wrote.

I have a question about taking the derivative of y= vxe^x where v is a function of whatever the fuck.
Would it be y' = ve^x + vxe^x?
I know y= ve^(2x) would be y' = v'e^(2x) + 2ve^(2x)

>>9258578
Stop being autistic

Can someone check my work? I feel like I did something horribly wrong

>>9260400
[math]y=v(x)xe^x \\ y'=v'(x)(xe^x)+v(x)(xe^x)'=v'(x)(xe^x)+v(x)(e^x+xe^x)=v'(x)xe^x+v(x)e^x+v(x)xe^x \\
y=v(x)e^{2x} \\
y'=v'(x)e^{2x}+2v(x)e^{2x}[/math]

>>9260428
Yes you've done it completely wrong.

>>9260502
Can you tell me where I messed up?

So e^(lnx) = X
What is e^(-.5lnx) = ?

>>9260607
Are you retarded or what?

>>9260611
Probably. I can't solve it even with a calculator

>>9260607

Use the fact that

aln(x)= ln(x^a)

to take the -1/2 inside the log.

e^(-.5ln(x)) = e^(ln(x^-.5)) = x^(-.5) = 1/x^(1/2) = 1/sqrt(x)

>>9260614
[math] a^{bc} = (a^b)^c [/math]

This isn't really math or science related

I just had a week long coding project with the final portion (worth the majority of the grade) being a group interview where we show the project and answer questions about it. We had a group of three. Both me and another group member were late. When we got to the room the prof said "you're late. please leave". i felt like contesting but i did as he said. i just checked blackboard and right now it's been graded 0/30. can he do this? Academically, I didn't do anything wrong. I contributed to the assignment significantly.

picture of the professor for reference. dude looks like a toe.

>>9259779
Can you write it as a power series and integrate term by term? Only one term will be non zero... basically the residue theorem reproved

Any optics people here?

I had an interview question the other day with a prof i want to work for and it stumped me.

"If you have a cavity with linewidth ∆ω (angular frequency), what is the maximum frequency at which you can use the cavity as an electro-optic modulator?"

I answered that this is not something I knew how to do. Anyone have an idea as to where to even begin this?

>>9260649
Did he say that he would do that in the syllabus? If there's something in the syllabus suggesting that policy he's got slightly better grounds to do so, but it's really questionable whether the university would actually back him up on it. Every university has a process for contesting grades, and your best bet is probably to work through that if he's being unreasonable.

>>9260694
just checked. nothing in the sylybus.

>>9260742
Then I'd talk with him about it. If he insists on being a dick, contest the grade. Absolute worst case scenario the university tells you there's nothing you can do, and he could get in serious trouble if he does anything that could be considered retribution for your having contested it. Might be worth talking to the department chair as well if you know her.

y'' = 2yy'
u = y'
u du/dy = y''
u du/dy = 2uy
du = 2ydy
u = y^2 + c
u = y' = dy/dx = y^2 + c
1/(y^2+c) dy = dx
x + c_2 = (arctan(y^2+sqrtc))/sqrtc

Did I do anything wrong here? I think there's something wrong for some reason.

>>9260761
you forgot about the solutions y=const

also, if you want to check whether your answer is correct, just plug it back into the original equation

Is it financially and academically possible to study medicine while also working part time to pay rent?

>>9260794
>financially
Maybe
>academically
Depends on your study habits.
If you're working to pay rent and school, it depends on your salary I suppose.
Think for yourself you faggot, no one knows you.

>>9256903

The whole idea of gravity is based on theory. There's no such thing as gravity waves. Throw all that Einstein bullsheeze in the trash. Rediscover Tesla. The universe is electric. Not gravity. Mathematics is a MODEL of creation. NOT CREATION!!!! Einstein divided by zero and got a singularity, I.e. Black Hole. Unfortunately, we have changed mathematical errors into an entire branch of science. Check out Stephen Crothers on YouTube. He destroys Einstein and his B.S. theories....Lol... As Above, So Below....

>>9260806
>faggot
Why the homophobia?

>>9260822
Why don't you fuck off and kill yourself?

>>9260847
>Why don't you fuck off and kill yourself?
What's your problem (other than the obvious homophobia)?

>>9260849
Right now? You are my problem, you fucking faggot bitch. Stop shitting the board up.

>>9260851
>You are my problem, you fucking faggot bitch.
cringe

>>9260853
"Cringe" is right - that guy was painful to watch.

To answer your question, I'm guessing you're new here. "Faggot" is used so casually on 4chan that it has pretty much lost its meaning in terms of sexual preference. It's more like "fool," but it initially had more punch. Sort of like the new generation is saying the F-bomb so much, they don't know what else to say to achieve shock value. So they just repeat it many times in one sentence.

So when you reacted to the actual meaning of the word, I think you blew the poor kid's mind.

Could we all be moving at the speed of light?

There is no center of the universe and there is no stationary objects in the universe. Speed of light is fastest anything can travel but all movement is relative. If there is 1 single object moving at the speed of light, then is there any reason you couldn't you say that object is standing still, and it's the rest of the universe moving at the speed of light?

I know there are some really complicated algorithms for efficiently factoring (I want the all the factors, not just the prime factorization) large integers, is there an efficient method (meaningfully better than trial division) that is comprehensible with undergraduate understanding of number theory?

I'd like to use stuff I can actually implement since I'm using it for my own educational purposes.

>>9260880
>Could we all be moving at the speed of light?

No. I feel like you didn't think very hard about this question.

If we all move at c then how does one car pass another on the road. Is it going faster than c, which is impossible, or is the other car going slower than c, in which case it isn't going c, which is a contradiction to your hypothesis.

Which Page has highest ranking out of 1 and 7?
if Page 1 has the initial value of 1,0?
And when will googolz stop using this algorithm?

is there a better alternative to darwinian evolution? I fail to believe that random mutations can be the reason for a whole species to have a flame thrower ass

>>9261094
they are no longer pure random when some of them get selected and some don't

>>9261196
that still somehow has to come up. I don't have a hard time believeing that once it exists, it will get selected, but I just don't see it grow organs to process chemicals randomly. Or could a child be born with a flamethrower ass any day now?

>>9261202
no it's a step by step process.
if humans somehow were selected by nature for a flamethrower, it would happen much faster.
also random stuff can be enriched and then suddenly deliver a quantum leap
that bombardier thing was not a bombardier thing in the beginning, it was just some gland

>>9261212
>it was just some gland
for what reason would the gland have been carried on before it had any actual use

What reasons could cause a seemingly perfectly healthy human to have a sufficiently bad arterial embolism, resulting in part of an arm being amputated?

>>9257673
assuming it's also bounded by x=0, like in pic related. a full rotation has a volume [math]\displaystyle v_{2\pi}=\int_0^1(x^2)^2\pi\,\mathrm{d}x[/math]
and a rotation of theta has a volume [math]v_{\theta}=\frac{\theta}{2\pi}v_{2\pi}\,,\quad \theta\in[0,2\pi][/math].

if it's not bounded by x=0, then just multiply that answer by 2.

>>9261213

it came from something 'with a use'
stuff like that develops from sexual and secretional glands, together with depots

>>9261216
a congenital condition plus some infection

>>9261228
Would Venous Thromboembolism caused by a combination of Polycythemia Vera, stress, and an infection fit the bill?

>>9261235
yeah sure, the cancer condition is a but freak tho
make the infection chronic and nosocomial, add a hidden stenosis or some fistula somewhere, and you got it pretty much

>>9261246
oh, and dont forget some risk factors like heavy smoking, anti baby pills, meth abuse, overweight, and the like

>>9261250
The point was that the risk factors aren't there.
I've just been looking for a reason that a happy, healthy mid-teens girl could suddenly end up needing an arm amputated without it being "car crash lol"

>>9261252
how about snake bite then or some exotic fish venom

for the definition of the limit at infinity being infinity, should [math]K(A)\in\mathbf{R}[/math] or should it be [math]K(A)\in X[/math].
does it change anything? if not, why are they equivalent?

>>9261427
The definition says that given an arbitrary distance A, then there exists a distance K such that:
if the distance of (positive) x from 0 is greater than K, then the distance of f(x) from 0 is greater than K.

>>9261454
>then the distance of f(x) from 0 is greater than K
sorry, meant A, not K

>>9261454
>>9261456
does f have to be defined at K then?

>>9261469
No, K is just a distance.

How do I make a matlab workspace presentable without having to rewrite all my shit on word?

Suppose you have two finite sets [math]A\subseteq B[/math] with [math]|B|\leq |A|[/math]. Is that enough to prove equality? and how

>>9261784
It follows from [math]|A| \leq |B|[/math] and [math]|B| \leq |A|[/math] implies [math]|A| = |B|[/math]. This is certainly true, but my set theory absolutely sucks, so I don't know if it's trivial or if it needs some autistic messy proof.

>>9261784
>Is that enough to prove equality?
Yes since A \subset B implies |A|\leq|B|.

What is meant by "instance of a random variable". Experimental data is just numbers, not really a random variable, so how should I be thinking of this?

>>9261784
>some autistic messy proof.
youre probably right. just found a proof for [math]A\subseteq B\rightarrow |A|\leq |B|[/math] on proofwiki, which i barely understand. still looking for the last part
>>9261867
but then how does [math]|A|=|B|[/math] imply the two sets are equal?

>>9261843
It is not trivial.
https://en.wikipedia.org/wiki/Schr%C3%B6der%E2%80%93Bernstein_theorem

can someone please tell me what the hell MyMathLab means here by "remove common factors"?

Obviously they're there, but I don't understand what it means, I don't see anything that's identical to anything else.

>>9261913
>but then how does |A|=|B| imply the two sets are equal?
Because A is a subset of B and finite.

>>9261925
You don't need that for finite sets.

>>9261937
>can someone please tell me what the hell MyMathLab means here by "remove common factors"?
>Obviously they're there, but I don't understand what it means, I don't see anything that's identical to anything else.
They cancel (y+4)/(y+4) in each expression, i.e. for the first one:

12(y+4) 6y / (3y+12) =
12(y+4) 6y / [3(y+4)] =
12 * 6y / 3 =
4(6y)

>>9261950
Oh jesus it really was that simple.
they should've just used the fractions with the factored denominators and it would've made it much more clear.

Thank you.

>>9261943
sorry i meant more what is the specific chain of implications
[math]\begin{align}[(|A|=|B|)\wedge (A\subseteq B)]&\leftrightarrow [(\text{there is a bijection } f\colon A\to B)\wedge \forall x(x\in A\rightarrow x\in B )]\\ &\vdots\\ &\rightarrow /\leftrightarrow [A=B] \end{align}[/math]

>>9261943
>You don't need that for finite sets.
Who assumed a finite set?

>>9261977 see
>>9261784

>>9261913
If the definition of the inequality is in terms of existence of an injective function, then for [math]A\subseteq B[/math], you can you take the inclusion map [math]\iota[/math] from [math]A[/math] to [math]B[/math] (which only means the identity function from a set to a set containing the first one), and we know that this is an injective function. So by definition, we get [math]|A|\leq |B|[/math].

We also know that there exists an injective function from [math]B[/math] to [math]A[/math]. This means that the first map is surjective, so the sets are bijective, therefore [math]|A|= |B|[/math].

>>9261982
I mean the map is bijective

>>9261982
>This means that the first map is surjective,
You need to use finiteness here [there's an inclusion {even numbers} to {naturals}, and there's an injective function from {naturals} to {even numbers} (n->2n) but that doesn't mean the first map is surjective].

>>9260880
Things obviously aren't all moving at the same velocity through space. But it's interesting to speculate that everything might be constrained to move at the identical velocity through spacetime, perhaps c or some function of c, such that increased rate of motion in the space direction would necessarily reduce the rate of motion in the time direction, and vice-versa, to maintain the constant overall speed. In this scenario, acceleration would simply be a change of direction through spacetime, i.e. a curved path at the same total speed.

>>9261970
The implication is only for finite sets, basically just using the pigeonhole principle, since all |A| elements of A are elements of B, and B has |B|=|A| elements, they are the same set.

>>9262001
True dat.

>>9261982
For the proof of surjectivity:
Suppose the first function not surjective, then we can find [math]b\in B[/math] such that [math]b\notin f(A)[/math]. Then the last injective function evaluated in [math]b[/math] gives us a unique [math]a\in A[/math], which is an element in the domain of the first function. But due to injectivity of the last function and the pigeonhole principe (only possible because [math]A[/math] is finite) we get a contradiction with its own injectivity.

Apparently we don't need [math]B[/math] to be a finite set, which makes this theorem or whatever a little more general than stated

>>9262035
thanks anon, but i dont get how the pigeonhole principle is used

anyway i think ive found the proof through using both
https://proofwiki.org/wiki/Subset_implies_Cardinal_Inequality
and
https://proofwiki.org/wiki/No_Bijection_between_Finite_Set_and_Proper_Subset

>>9260666
Think of the linewidth as the resolution on your modulator. In the limit of infinite frequency, you lose your modulation ability because all the pulses smear together. In the limit of low frequency, the linewidth is irrelevant because all of the pulses are so far apart. Somewhere in between you find a frequency where the band of one pulse begins as the band of the previous pulse ends.

>>9256515
pepe is an stand in for the person speaking, and is there merely to demonstrate how the poster feels or som other point best made with imagery.

Pepe in particular is popular with disaffected men, and it just so happens that these men tend to be interested in science.

Well, Economics is a science, right?
/sci/ thoughts on Cambridge controversy?

>>9256515
It's not about /sci/, it's about 4chan in general. He's our mascot, kinda.

Memes aside could someone explain like I'm five why Bogdanoff Twins physics are wrong?
Their propositions seem pretty logical to me.

Can machine learning create OC or just mixes different ways of thinking, art and writting styles, etc...?

Can TMS harm your brain in the long run?

>>9262094
>Well, Economics is a science, right?
No since economists don't use the scientific method,

>>9262098
>Their propositions seem pretty logical to me.
Which ones?

>>9262101
what is OC, if not for a mixture of different ways of thinking, art, and writing styles?

Does anybody have that math textbook flowchart that some anons worked on in a thread a while back? I looked around the archive but couldn't find it.

>>9262138
isnt it on the wiki?

>>9262111
The retarded kind actually does.

>>9262285
>The retarded kind actually does.
Huh?

>>9256335
Is it possible to break down a skill into smaller skill sets?

Would this be practical?

If so how would each of the levels of subset be categorized?

I need help figuring out what books in this series of anime memes (1/3) are repetetive, unnecessary, or low quality and what isn't, or perhaps what has been wrongly excluded. I'm having a lot of trouble lining up books to the topics in the various "fields of mathematics" lists.

>>9262138
Hello.

>>9262428
2/3

>>9262433
3/3

>>9262435
Lang is a meme.

how do you make math fun

how do you go about solving this? I tried using quadratic formula but no luck

>>9262460
google it

>>9262460
Try getting that x to the right hand side and squarring both sides.

>>9262460
let y=3x+10
then
x+sqrt(3x+10)=-2
(y-10)/3 +sqrt(y)=-2
y/3 +sqrt(y)=-2+10/3

use quadratic formula (it's a quadratic in sqrt(y)) then backsubstitute for x

>>9262460
just google fuck

>>9262460
[math]x+(3x+10)^{1/2}=-2 \iff (3x+10)^{1/2}=-(x+2) \iff 3x+10=(x+2)^2
\iff 3x+10 = x^2+4x+4 \iff x^2+x-6=0[/math]
The rest is on you.

>>9262479
>(3x+10)^1/2=−(x+2)⟺3x+10=(x+2)^2
Wrong.

>>9262485
?

op here

i got the answer as -3

>>9262469
quadratic fo. definitely isn't what you do here.

>>9262462
>>9262466
>>9262473
>>9262479


question? am i brainlet?

>>9262488
>quadratic fo. definitely isn't what you do here.
Why not? It works fine, you'll get -3.

>>9262486
>?
What are you confused by? Your statement is wrong.

>>9262492
Care to explain why?

>>9262493
>Care to explain why?
Try to explain why it's correct and you'll hopefully see why it's not.

>>9262495
It's the iff you complaining about right?

>>9262498
>It's the iff you complaining about right?
Yes.

>>9262499
Yeah, it's 'cause /iff is so much easier than /implies. I need to stop being lazy. Thanks.

Is mayo an instrument?

>>9256335
I got hydrogen fluoride in my eyes a few hours ago by burning difluoroethane from an air duster. It burnt my eyes for a split second and then burnt my nostrils for a split second. I made sure to rinse both with cold water from my sink and shower, and rinsed my eyes out for like 10 minutes, even with some soapy water. How fucked am I in a few hours?

>>9262515
How about calling the fucking line for accidents instead of asking us? How about calling a fucking doctor?
Jesus Christ, you guys are dumb as shit.

>>9262508
Wow, nice meme. Welcome to 4chan, man. Here we're really into big danky memes. Hey, lemme tell you something, this following board has some pretty dope shit:
>>>/b/
Keep yourself there.

>>9262523
I mean it was outside, and I was a few feet from the source, so I should be good right?

>>9262539
I don't know, I'm not a chemist.
I'm serious, when something like this happens, you should ask someone that you can really trust, not 4chan. You could really get yourself hurt by doing that, either by doing something stupid someone say or by not getting professional help in time.

>>9262539

jesus christ,

what the fuck were you doing?

I've studied all the books used by my university for their undergraduate mathematics program.

What do I have to do to make them met me do the final year of a BSc honors with them?

How do I prove myself?

>>9262560
Challenge all the prerequisite courses. Ask a counselor for the paperwork.
Dipshit.

>>9262544
i sprayed some compressed air fluid onto a paper towel and lit it on fire to see if it would

I've read that there's no way to solve algebraically something that has x's as exponents and as regular terms, is that true? That sounds like bullshit to me but at the same time I have no idea what to do since logging doesn't seem to accomplish anything here.
Is algebra not this perfect system that solves everything like it was back in high school?

IF WE CAM3 FRUM MONKeys DFEN Y R THERE stILL MONKEYS??

chekcmate atheists????;;;'";

>>9262574
>I've read that there's no way to solve algebraically something that has x's as exponents and as regular terms, is that true?
define "regular terms"

But yes, once you're working with polynomials of degree at least 5, there's no general solution analogous to the degree 1/2/3/4 cases:

https://en.wikipedia.org/wiki/Abel%E2%80%93Ruffini_theorem

>>9262580
I don't think that is what I meant. Sorry, I forgot a lot of the terminology so I don't know what to say other than "regular terms".
Basically what I meant was something where you have an x and an e^x.
I was just messing around with what would happen if you combine an exponential decay equation with a linear equation, and I realised that I couldn't figure out how to calculate x for a specific y value, and when I looked it up it seemed to be saying that it's impossible algebraically. Which just shocked me because it doesn't seem like a particularly complicated thing.

>>9262601
>Sorry, I forgot a lot of the terminology so I don't know what to say other than "regular terms".
Maybe you mean transcendental function/equations?
https://en.wikipedia.org/wiki/Transcendental_function
https://en.wikipedia.org/wiki/Transcendental_equation

>>9262515
do your eyes hurt atm?

>>9262574

I'm probably retarded but in an example we have:

SA = x^2 + 100/x^2

SA = x^2 + 100/x

What happened to the x^2 in the denominator?

>>9262934
Well duh, there was a typo. Have some confidence in yourself, you're not a little kid anymore.

>>9262961
Well if I correct the typo it fucks up the rest of the thing and I get a quartic where there should be a cubic.

>>9262934
>>9262961
>>9262967
never mind I fucked up something really simple beforehand

>See picture for problem
I have to give the Resistance for R2 so that 10 amperes wil go trough R1. resistance for r1 is a given: 0,5 ohms, voltage source provides 15 mV.
Im mainly having problems with the math, how do I calculate the ratio in which the current divides?

I feel like a complete retard right now, but if an oxygen ion has a charge of 2-, what does O2 have? 2-? 4-? How do you know what the charges of the allotropes are?

>>9262979
the resistors are in parallel, so R2 will have no effect on the current through R1 assuming it's not a short.

>>9263035
O2(g) has 0

>>9263043
I just used oxygen as an example, I want to know how you actually find it out for yourself for different allotropes. Do you just look it up on a chart or what?

>>9263039
the current coming from the scource will increase because the total resistance will either increase or increase depending on r2. The idea is R1 is an Amp-meter with an inner resistance of 0,5 ohms, without r2 the amp meter would give a result of 15*10^-3 / 0,5 amps at 15 mV.. However, we want it to show 10 amps at 15 mv. To increase the current we add a resistor in parallel.

>>9262979
Resistance of circuit: R = (R_1 * R_2) / (R_1 + R_2)
Current through battery: I = U / R
Since the resistors are connected in parallel, the voltage drop is the same: U_1 = U_2 = U
and the sum of the currents through both resistors is I: I = I_1 + I_2
Ohm's law for both resistors: I_1 = U_1 / R_1; I_2 = U_2 / R_2

Unknowns: R, I, I_1, I_2, U_1, U_2
There are six unknowns and six equations, so you can solve for R_2.

>>9263061
Oops, I_1 is known (10 amperes)

>>9263052
Whelp, after doing some more Googling I realized that the charges are displayed in the structure diagram. Is there really any need to know how to find this information without using the structure diagrams?

>>9263054
>the current coming from the scource will increase because the total resistance will either increase or increase depending on r2.

that doesn't change the fact that there's only 15mV across R1

>To increase the current we add a resistor in parallel.

you will increase the total current in the circuit but you will not change the current through R1 unless it's a short

>>9263061
I1 = V1 / R1
10 = 0.15 / 0.5
sure bud

>>9263071
0.015 but whatever still impossible

>>9263071
>I1 = V1 / R1
>10 = 0.15 / 0.5
>sure bud

Whoops, I guess you can't change the current through R1 then. Wtf kind of problem is that?

>>9263071
>>9263078
>>9263091

Maybe I fucked up my english, so I put the problem trough google translate which says this:

>An amp meter has a resistance of 0.5 Ω and gives a full scale output at 15 mV. Calculate how large a parallel resistance (shunt resistance) should be so that the full scale output corresponds to a measuring range of 10 A?

>>9263108
alright I think I get it now

R1 is a galvo with a resistance of 0.5 ohms and a full scale voltage output of 15mV, meaning that it has a full scale current output of 30mA

to answer your question on how current divides
[math] \frac{V_T}{I_T}=R_T \\\
\frac{V_T}{I_T}=\frac{R_1R_2}{R_1+R_2} \\\
V_T=V_1 \\\
\frac{V_1}{R_1}=I_1=I_T \frac{R_2}{R_1+R_2} [/math]

so simply plug in your numbers and solve for R2

What is a good book on logic and algebra for beginners?
I'm a first year CS brainlet and I'm having trouble understanding stuff

Is it right to say that for a temperature field in a plane given by T=xy, the isotherms are x and y?

alright guise

could i get a step by step for this one?

>>9263305
factor out the (x-2)^{-1/3}

>>9262574
What do you mean by "solve" ? log(x) literally means "the number y such that e^y = x" and sqrt(x) is "the positive number y such that y^2 = x". It certainly answers the question "what's the solution to e^y =x" but whether or not you find this satisfying is up to you (not wildberging here, not saying that logs don't exist or anything, just trying to make anon think about what it means for an equation to be solved, because it's pretty interesting).

>>9263312

like this?

wtf is (x-2)^(-1)?

Could someone help me understand special relativity? Like, walk me through it like I'm 5. I understand there's light involved and that it travels at the same speed no matter what, doesn't go faster if it's located on something that's moving. And for the person on the moving part, it's moving at the same speed, idk about the one outside of the moving system. Anyway, I don't get it because everyone's explaining it in some weird way as in light bouncing off of mirrors or some other crap.

Why is the linear equation what it is? Is it because it maps every single point on it? I don't know how to think of math equations. ax+by=0, if this statement is true for some point, that means it lies on the line. So is the math equation of a line just a mathematical representation of all infinite points that lay in it?

Sometimes I wonder if I'm autistic...

>>9263437
>is the math equation of a line just a mathematical representation of all infinite points that lay in it
Yes.
>Sometimes I wonder if I'm autistic
Yes.

>>9263437
Yes.
The correct representation would be [math] \{ (x,y) : (x,y) \in \mathbb{R}^2 \land ax+by=0 \} [/math] .

>>9263305
I wrote down the answer for you and made a picture of it.
I used a lot of steps and I even made some notes to show you how I solved it. I haven't slept in 36 hours and i'm just a first year student so maybe its wrong. But its probably correct.

>>9263622

am i brainlet?

I'm first year too, however, it would have taken me the whole afternoon to figure that out. I can't make any sense of the text book, it might as well be written in ancient greek

>>9263698

I was literally like that. I always freestyled math to very bad grades and it all seemed very complicated. Then I started from the beginning again, learned all the basics and now shit like this is piss easy. It's literally 1+1=2. But you need to start from the bottom again probably.

What are matrices and determinants? How do they relate to each other, and what are their applications? Literally the ONLY thing I know is how to SOLVE, nothing else. This isn't a way to do math. My country is fucking retarded.

Hi, can someone please check my proof (I'll post just the idea of the proof to make it simple):
I need to show that [math]L(V, F)[/math] is a vector space (where F is a field and V is a vector space) and L is the
set of all functions from V to F.
We need to show the following properties:
>Addition is commutative
If we take [math]f_1, f_2 \in L(V, F)[/math] then the sum [math]f_1 + f_2[/math] is the sum in the field F. Then, by definition
of a field, such sum is commutative.
>Addition is associative
Same thing as the commutative one. It follows from the field sum.
>Existence of the 0 element in addition
Define [math]0:V \rightarrow F : v \mapsto 0[/math], which is well defined since the identity element exists by definition
in a field. So [math]f_1(u) + o(v) = f_1(u)[/math]
>Existence of the inverse element in addition
It follows from the fact that the sum of two functions in [math]L(V, F)[/math] is in F and, since it's a field, every element
has an inverse one which when added equals to 0 (identity).
>Identity in multiplication by scalar
>Zero element in multi. by scalar
>Associativity in multi. by scalar
>Distributive laws
Follow the same idea as the addition ones.

i just scored 91 on a 25 minute iq test.

am i retarded?

>>9263941
Yes

>>9263868
looks good

>>9263957
Nice, thanks.

>>9263941
no, retardation is only below 70 i think

>>9264051
Don't enable him, cunt.

>>9263807
If you are new to Linear Algebra, then this series is very good
https://www.youtube.com/watch?v=kjBOesZCoqc&list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab

>>9263807
>My country is fucking retarded.
Which one is it?

>>9263868
yeah, it's fine

So I'm supposed to prove [math]\int \int \int_{E}f(x,y)dxdy[/math] exists and calculate it's value. What I thought I'd do was calculate the integral for the [math]x^2+y^2\leq z^2+1[/math] side and substract the integral for the [math]2z^2\leq x^2+y^2[/math] side, but [math]\sqrt{x^2+y^2-1}[/math] is troubling me.
Does [math]\int \int \int_{E}f(x,y)dxdy[/math] actually exist and if so, how should I solve?

>>9264179
Forgot the picture.

>>9264061
Thanks, you're not the first one to recommend this actually, other anons have suggested it related to my other questions. I'll have to watch the entire thing when I have time.

>>9264068
Croatiastan.