Why are we as humans so drawn and moved by music although we are a species that primarily focuses on its visual sense? Why aren't we usually not as moved by visual art? We can look at a statue and be greatly impressed, but we will never get back at looking at any statue as often as we get back to listening to a song we like.
Even animals are drawn to music and listen carefully. Why? How does this attraction work?
Music is often hypnotic because of beats and rhythms and shit
Most visual media is not
>>8618894
Wait, how does the Mandelbrot set relate to the logistic map?
>>8618898
i have no fucking idea i'm just an idiot who saves cool pictures
Can anyone with a better understanding of optics help me out?
This isnt homework, obviously, but a practice test for my coming physics finals.
The question is:
>An engineer checks a part by shining white light in a 45° angle on a Silicate plate with an index of refraction of 3.9, which has a thin layer of Silicium-Oxide on the outside, with an index of refraction of 1.46.
>The thin layer shines in the correct kind of green, which proves to her that it has the correct thickness.
>a) How thick is the layer, if a wavelength of 560nm is assumed?
>b) Explain mathematically why she looks at it at an angle, instead of straight at it?
Now Im certain that this has to do with the fact that the index of refraction is dependent on the wavelength, and so the light will be split up into different angles for different wavelengths.
However I couldnt find a formula for that relation anywhere, and Im confused by the fact that the index is given as one specific number.
I will follow with what I have so far, but its not much.
Help greatly appreciated.
Phonepost because lazy...
Put the question in google. You're welcome.
>>8618819
This is what Ive come up with:
>The light hits the first border, and the different wavelengths get separated.
>They then hit the second border, and get partially reflected at the same angle as the angle of incident.
>They hit the first border from the other side, and get refracted again.
But now they are all at the same angle as they were before,except on the other side of the normal.
All wavelengths are at 45°, but they are spaced apart slightly.
The angle is thus not related to the thickness of the layer, and I cant find the answer.
What am I missing? Does it have to do with total reflection upon hitting the first barrier the second time or something? I dont get it.
Why do emotional stress affect our physical body? What's the evolutionary purpose of this?
>evolutionary purpose
Quite the memester, aren't you...
Evolution has no purpose, tons of good, bad and neutral variations occur, good and neutral ones survive, bad ones don't. This doesn't happen via a guided mechanism, it is random.
There is no way to suggest emotional stress is beneficial to survival or reproduction yet. I might just have no effect
>>8618802
I agree that effects of emotional stress isn't something connected to the prior benefits, it's probably a random consequence
But I'm getting tired of this "purpose of evolution" semantical nazism
Of course evolution doesn't have a purpose, fucking duh
But it is much more convenient to word it that way than saying "how was that mechanism beneficial for this organism to he point that it is still here/widespread/bla bla"
>>8618823
it doesn't have to be beneficial for it to be widespread
your rewording is still as retarded as
>What's the evolutionary purpose of this?
is the multiplication induced by C the only one that makes R2 a field?
>>8618790
yeah
any field extension of R by adding a root of a polynomial must be of degree 2 (only degree 2 polynomials are irreducible and don't give R as an extension), and any finite field extension is of this form (otherwise for a new element c there's an infinite subbasis basis c, c^2, c^3, ...). so all we need to see is how R extends by roots of quadratic equations
for an irreducible polynomial x^2 + bx + c, we add sqrt(b^2 - 4c), a root of a negative number. but sqrt(4c-b^2) is positive so dividing we get i. and R[i] = C
that means we have C inside all of them, what about other copies of C? C only has two automorphisms, the trivial one and the one that goes i -> -i. I'd say that's all
so yes, it's always C, and even if you don't consider it up to isomorphism, there are only two ways to extend it
>>8618812
I didn't fully understand the post. Could you at least tell me where I could look that stuff up?
>>8618812
OP is talking about making R2 a field, not making it complete.
So consider the operation (a,b) + (c,d) = (a+c,b+d) and (a,b)*(c,d) = (ac,bd)
Proof of associativity:
((a,b) + (c,d)) + (e,f) = (a+c,b+d) + (e,f) = (a+c+e,b+d+f)
And
(a+b) + ((c,d) + (e,f)) = (a+b) + (c+e,d+f) = (a+c+e,b+d+f) = (a+c+e,b+d+f)
The proof for multiplication is the same.
The proof of commutativity for both operations follow from the properties of operations of real numbers.
The additive identity of obviously (0,0) and the multiplicative one is (1,1).
The additive inverse of (a,b) exists and is (-a,-b). The same goes for multiplication.
The big one: Distributivity
(a,b)*( (c,d) + (e,f))) = (a,b)*(c+e,d+f) = (ac + ae, db + fb)
But also
(a,b)*(c,d) + (a,b)*(e,f) = (ac,bd) + (ae,bf) = (ac + ae,bd + bf)
This completes the proof.
Reminder that the operation induced by C is (a,b)*(c,d) = (ac - bd, ad + cb) so the operation described above is clearly different.
Exercise: Find another operation that makes R2 a field and prove that it is.
French math-fag here. I'll have to learn/use Caml this year.
How bad is it ?
>>8618641
>French math-fag here.
Kek.
It's pushed heavily by French academia because your state and industry sank a lot of money into it's development, there is no good reason to use it besides politics.
It's not a bad language per se, there as some interesting and big projects in it, but you rely A LOT on libraries written by (french) PhD students who no longer care about it and abandoned them. Also less tool support and libraries and support via community than Scala, Haskell or even LISP.
>>8618641
i had to learn and use it a few years ago, its a shit one, really annoying language, its useless since its only used for education, and has no real practical application, just do it, and do worry, in a few years you'll be doing real programming with java or C++
>>8618754
do not* worry
ITT: List of theories in statistics.
>>8618078
what the fuck you start.
>>8618078
>Central Limit Theorem
>Law of Large Numbers
What's the point of this thread?
>>8619698
What's the point of anything
>have a few free electives to take before I graduate
>take a political philosophy class because I'm interested in learning about it
>first day of class professor spends the entire class period talking badly science and asserting that pursuing science is a waste of time because you should be pursuing philosophy
I dont get why philosophy and science hate each other, specially hard sciences.
They are both needed
>>8617841
I've never taken a science or math class in which the professor mentioned philosophy
>>8618303
But here in /sci/ every talks shit about all social/human sciences in general and act like they are superior for studying STEM.
Also I met a engineering professor who every class talked shit about law school.
Is it worth transferring to UNSW just to meet the man, the myth and the legend?
yes, become his acolyte, op
Yes, and when you publish your thesis on rational approximations to Sqrt[2] with decimal expansions consisting of less than 10^21 digits, you will land some really prestigious professor gigs the like of Harvard, Yale etc
>>8617677
I would.
When I graduate I will unironically apply to go gradschool there. If I get accepted to somewhere better then I won't go but if I don't then... time for my PhD thesis in rational analysis.
O'neill cylinder is still a realistic design for big space habitat?
>>8617556
>big space habitat
>realistic
why live where there is nothing?
>>8617578
>wanting to live in a gravity well
Good goy.
>>8617556
Yes. Bernal sphere is more efficient though
What would be the aftermath if Pakistan and India went to full out nuclear war ? How would it affect the planet and the areas of those two countries ?
Badly.
Goodly
Okayly.
Has anybody here learned algebraic geometry straight from EGA?
I am starting and I find it a much better source and more readable than basically any of the EGA-lite books like Hartshorne, but I need tips. So far I have read some of chapter 0 up to ringed spaced and ch 1 on schemes, but the immensity of this reference is overwhelming.
I have heard that many things in EGA are no longer considered important, so I just need advice on what to skip.
My goal is to profitably read SGA1 and SGA3, especially SGA3 and stuff on group schemes.
>>8617419
One time a young student at Cambridge was studying Algebraic Geometry and stuck on a particularly difficult problem assigned to him. Meanwhile, the great A Grothendieck was to give a talk at the university and the student was not to miss it. After the talk, he sheepishly approached the wizard and asked him about the homework problem. Grothendieck mumbled "EGA Section whatever paragraph number" and the student walked away. Sure enough, upon finding the tome in the library, there was the solution to his problem, laid out in the text. The student relaid this tale to his professor, JG Thompson, for he could not now honestly write up the solution. Thompson remarked "I don't know if I should give you an F for looking it up, or an A for having the balls to ask him about it."
That students name? Richard Foote.
>>8617451
Cool, where did you get that anecdote? Also isn't Foote a (finite?) group theorist? lol
Have you read EGA? Are you basically telling me that I should be able to quote it chapter and verse like the bible?
>>8617419
I'm 95% sure reading EGA is a waste of your time. If you had a professor fluent in algebraic geometry nearby, you wouldn't be asking a board full of undergrads what to read. You probably don't have a nearby algebraic geometer so you probably aren't planning to do research in algebraic geometry, which is the only good reason to be reading EGA instead of something more accessible/less time-consuming.
Trying to filter down EGA into a barebones graduate-introduction course is stupid, especially since you'll need another book anyway to find problems.
it was a critique on advance math, Caroll didn't like imaginary numbers, he thought they were insane
Pretty sure it was about madness not drugs
>>8617181
>he thought they were insane
How can complex numbers be insane if they aren't people?
>not reading Euclid and His Modern Rivals
Alice in wonderland a shit
Why there's 5000 patents that are forbidden and their inventors put in jail under security reasons?
Before you go back to >>>/x/, can you tell me what you mean?
>>8616993
https://www.google.com.co/amp/s/www.wired.com/2013/04/gov-secrecy-orders-on-patents/amp/
I will start, vibrations (grad).
>Be first day
>Professor explains syllabus
>Everything ok
>Professor now explains Springs, still ok
>Complex numbers appear
>Integral average with complex numbers
>We are 30 minutes into the first class and doing signal processing
>tfw haven't done any complex math in 2 years
>tfw it's only the first week
>>8616579
Precalc
>>8616579
>Physics: Mechanics
>Methods of Lagrange and Hamilton
>Continuous media using Fourier series
>Mathematical formulation of the dynamics of a particle and systems of particles, including applications to atomic physics
>Civil engineering major
>>8616579
Pre-algebra
Hey, /sci/ quick question about gravity. If gravity is real, shouldn't all spheres have gravity if the Earth does? Why can't I float marbles around a bowling ball?
>>8615812
is this a real question ?
>>8615812
a bowling ball is sitting on the fabric of space time if its in earths gravity
Obviously because gravity is a hoax OP