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Reminder: /sci/ is for discussing topics pertaining to science and mathematics, not for helping you with your homework or helping you figure out your career path.

If you want advice regarding college/university or your career path, go to /adv/ - Advice.

If you want help with your homework, go to /wsr/ - Worksafe Requests.

Can I make it in pure maths if I’m only pulling a B in precalc?
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If you tried as hard as you can and studied a lot and still didn't get the highest grade then yes you are stupid. If you just half-assed it and still got a B then you're probably pretty smart. It's all relative, my man
I didn’t try as hard as possible but I also wasn’t complacent. I did take a couple hours to study before tests
nobody cares about your grades (besides the ones you got in your master for your thesis), only the school you went to or the impression you give in cover letters
I am a mathematician who teaches math. You are not doing shit in pure math i you have an 86% in pre-calculus. Sorry bro you're stupid.
again nobody will care about your grades, especially the ones you've got in undergrad

The age of the universe at 13.7 billion years is based on the assumption that space is expanding and time is not. But if time is expanding then this number is wrong. Or rather it is only correct from a single reference point. A reference point that is likely very back in the past.

If you were to assume that time is expanding at the same rate as space then it should be possible to find out a true age of the universe. The universe has an age that is absolute and one that is relativistic based on the expansion of time.

For example if event B happened 1 second after event A from the reference point of right now. Then many years in the future after time has sufficently expanded, we could say that event B actually happened 2 seconds after event A and this would atually be correct since time is expanding.

What makes this even more intresting is the idea that time is expanding in both directions. This would mean that future events are getting further away from us. And if time truly does have more than one dimension, then i am not sure if the current understanding of physics is sufficient to predict the future at all.
What evidence of time expansion is there?

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What element is the universe converging towards, given infinite time?
nothing, matter will all disappear in about googel years
Iron. Given that most stars end their lives as big dense balls of iron, until they finally disintegrate over ungodly amounts of time.

Though, in the end it will just be stray photons & free protons if they never decay.
Iron-56 if protons don't decay
the universe "converges" towards maximum entropy, ie a totally isotropic distribution of matter and hence probably no elements as we know it (because they have a strong internal structure)

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Formerly >>11186289
Just ask wolfram edition.
By the by, tallied questions a bit later today.
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>but in the context of a riemann intergra
Look up the precse definition of a Reimann integral and then consider the Reimann rearrangement theorem.
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Draw a free body diagram of the car as if it is accelerating on the flat. Call the axis parallel to the ground the x axis, the axis perpendicular y. There is a retarding force R on the car that opposes its motion, there is the force of gravity W, there is a normal force N, and lastly there is the traction force F.
Sum the forces and apply newton's 2nd law. The car obviously does not accelerate in the y direction, because W=-N. The acceleration in the x dir. is a=(F-R)/m. But, you know that a=Δv/ Δt which are both given. Plug that into the previous equation. Solve for F. Now apply the definition of power above.
So I got some magnets and I got me some saturable ferromagnetic material, how do I calculate the potential energy of various configurations of magnets and ferromagnetic material in 3d space? I know I probably need to do FEA, but what kind of FEA? What operations do I need to carry out in FEA to get potential energy?
what's with all the goddamn furry shit?
Look up "magnetic dipole moment".

Magnetic PE due to a dipole moment m is [eqn] U=-\mathbf{m}\cdot\mathbf{B} [/eqn]


What's the difference between a function and a relation?
1 reply omitted. Click here to view.
> shared by two (or more) elements of a given set,
"2 or more" is irrelevant, there is no distinction here between a function and a relation since you can define a function on a product of sets.
Without this distinction, what you are saying is that they are the same, which is not true.

The major difference is that a relation can be multivalued while a function cannot (a multivalued function is indeed not a function).
A minor difference is that, when talking about a function on a set, it is implied that the function is defined on the whole set (domain). If a relation is defined on a pair of sets, there can be elements of the first set that are not assigned anything.
>Without this distinction, what you are saying is that they are the same, which is not true.
where did I say that they were the same

fundamentally you're not looking at the same thing
a function is a transformation
a relation asserts equivalency or order (in the strict sense of it), or more generally a link between two quantities, which can be a transformation but can also be much more general

"x R y means that x and y are both even or both odds" is a relation of equivalence that's not a transformation
in more general terms, you can say
"x and y are linked by the relation x = 4y2" but that's abuse of language

>The major difference is that a relation can be multivalued while a function cannot (a multivalued function is indeed not a function).
literally semantics
>"x R y means that x and y are both even or both odds" is a relation of equivalence that's not a transformation
f(x, y) = 1 if x=y mod 2, 0 otherwise
There you go
Technically you can make a relation out of any function (and vice-versa), however as I said, the point is that you're looking at different things.

When I say "function", I think of topological and analytical properties. (is it continuous ? is it analytical (in the complex planes) ? is it convex/concave, what equations does it obey, etc...)
When I say "relation", I think of algebraic and set theoretic properties (what are the classes of that set which verify the relation, ie, for all x, y in S, xRy")

The example I cited is a bit trivial as a relation, but at least it gives rise to the group Z/2Z and define parity (which is a useful algebraic concept).
As a function, "f(x, y) = 1 if x=y mod 2, 0 otherwise" has no real interesting properties. The "arrival" set isn't even Hausdorff.
Every function is a relation but not every relation is a function

Apostol? Courant? Heh, I feel sorry for you 120IQ people. The only Calculus book that should be considered 'hard' and 'worthy' is Sternberg, all others are child's play in comparison.

It truly is amazing how they managed to create a book that only the true intelligent people can understand, you could say Apostol and Courant are a little hard in comparison to most math textbooks out there, but even with some effort, a brainlet can still go through them with certain ease, but Loomis and Sternberg's Calculus is on a whole nother level.
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Can anyone recommend me a good calculus book? :3
I know you're baiting but that book isn't that good. Sure, it tries to give you the big boy equations and to give you a lot of stuff that students usually see in Analysis, but the goal of calc is to make you familiar with symbols, integrals, and derivatives. In other words, to give you the mathematical maturity you'll need in more advanced topics.

You need to learn to walk before you run, and you need the mathematical maturity to deal with functions, integrals, and derivatives easily before you understand their deeper mathematical meaning.

Rudin, Bourbaki. Rudin is actually really good if you're able to prove the missing steps in his theorems on your own, if you can link geometric intuition to abstract notations ; in essence, if you've got the mathematical maturity which calc and baby linear algebra usually give you. Rudin however is not very good on its own, it's better to get another book with more motivation on the side.
Alfhors for purely complex analysis (very good geometric insight).
>arab and european
why did you repeat the same word?
if you are referring to niggers and pakis flooding europe at the joy of Israel, you are mistaken to categorize these mongrols and inbreds as arab. When I first saw the image, it looked as if she was egyptian or something but the longer I look she look like some tanned European, and then again I think arab. Im not sure really.

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Last one of these summaries in this year and decade.
Let's talk about what happened in science this November.
Will post pastebin with sources later
Pls comment if you spot any inaccuracies.
If something is missing: the selection is based on that Wikipedia list at the bottom.

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Reminder that it's perfectly possible for this to actually be the base reality, not simulated. The great filter actually exists and will prevent humanity from achieving any significant transhuman state capable of high-level universe simulations.
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I'm gonna phillip k dick in your ass
Every counter-argument for the simulation hypothesis begins with the (often unmentioned) assumption that a parent universe MUST have all the limitations of this universe. That is obviously not the case; if the universe is a simulation then any limit which exists could simply be artificial. There is no aspect of the universe which can't be simulated if we keep that concept in mind.
What do you mean by holes? The only flaw with the simulation hypothesis is that it's unfalsifiable and the evidence is statistical in nature and based on a lot of unknown parameters. It's arguably unscientific but it's perfectly possible.
Can someone explain to me possible ways that a simulation could actually take upon some sort of physical existence? Our current simulations are glorified spreadsheets, and even if they became more advanced they would still be purely abstract.
First, consider what your perception of "reality" is. Lets simplify things a bit and say that "you" is your brain (putting aside stuff like the nervous system etc). When you "see" something, actually it's just your brain getting electric/chemical signals. When you hear, it's actually just your brain getting electric/chemical signals. This goes on for all senses. In conclusion, everything you sense is not reality; everything you sense is merely electric/chemical signals.

Expanding on this, there's no way for you to actually know if anything outside yourself actually exists; maybe those signals being sent to your brain are actually NOT from an organ that is registering real light hitting cones. Maybe the signals are just being sent from a simulator. This concept was explored in the movie The Matrix, although even earlier than that there was Rene Descartes "Evil Demon".

Okay, so maybe everything in the universe is a simulation, but you're not, right? Lets go deeper. What if you made an exactly perfect, flawless scan of your brain, down to the subatomic particles, and even deeper, and then ran it in a perfect, flawless physics simulator on a computer that had infinite storagespace and energy? Also, the computer will feed in the exact same fake data that the "evil demon" was feeding you before. What would this simulated brain experience? If the simulation was truly perfect, then it would feel the exact same experiences you are feeling right now.

In conclusion, you could be in reality now, or you could be in a simulation. There is literally no possible way for you to ever test this or prove it isn't true. There is absolutely no perceivable difference you could ever find to disprove this concept.

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>Kanazawa is an autist idiot who got fired for saying black women are ugly

no give me data not opinions
ITT: We pretend confirmation bias is more important than statistically significant data.
All the data we have on the economics of migration comes from western countries with strict immigration standards and isn't applicable to an open borders scenario.
So, where's your data to back up your opinion?

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Despite throwing yourselves into advanced mathematics, many of you lack comprehension of the fundamentals from your elementary days.
18 replies omitted. Click here to view.
>he forgot you read left to right rule, too.
Its okay, its a rookie mistake.
5-4(3-1)/2 +6-7
This what would be written if OP wasn't a fag
It's this you retard
It's pretty easy to solve if you formulate it correctly in your head 5-4/2*(3-1)+6-7
You don't even need to know PEMDAS
If all you know is that you have to solve the parenthesis first then you can easily do it. What makes it ambiguous is the division signal that no one ever fucking uses.

Do you believe in this nonsense? Ooo aaa ooo ahhh hoo hoo hoo wak wak wak(monkey and ape sounds)
Pathetic bait
No wonder we won the homo war, fucking manlets never learn.
No. We might have evolved from habilis, but no way we evolved from erectus-neanderthals. Look at the skulls, several changes would have to go exactly backwards for that to be the case. It seems H. naledi may be our closest known ancestor.

Formerly >>11183694
Classification of the cubics edition.
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its minimized at N=14 with expected number of presses equal to 13.64...

its calculated as 100/N + (N-1)/2
its the expected number of random presses needed to land inside the range + the expected number of next presses needed to get to the desired track

massive brainlet here, I need help

Is there a book with math problems that will help me practice and take me from beginner to advanced?
I'm particularly interested in analysis, linear algebra and proofs of all kinds
I know basic logic (truth tables and such) and did some calculus in school but I always sucked at it.
Can /sci/ help a calclet? Prove/disprove: the set of all (real-valued) continuously-differentiable functions [math]f[/math] on the interval [math][0,1][/math] s.t. [math]f'(\frac {1}{4}) = f'(\frac {3}{4})[/math] is dense in [math]C[0,1][/math] under the sup-norm.

I thought that [math](x - \frac {1}{4}) \sin (\frac {1}{x-1/4})[/math] or a similar function whose slope goes nuts around [math]\frac {1}{4}[/math] might prove to be a counterexample, but I'm having trouble formalizing my reasoning and I'm not entirely sure it's correct in the first place.

> "Women in mathematics" is an organization at my uni
> I don't go to their events because I'm afraid it will be feminist cock and ball torture
> This time I went to one because I didn't know it was their event
> only two undergrad girls show up
> one of them sits in the back with her BF
> the other is a CS major (I.e., subhuman)
> There are a bunch of female grad students
> They probably outnumber undergrads
> Not a single male grad student
> about 5 undergrad boys show up

Really makes me think
Oh its absolutely true. By weierstrass approximate it with a polynomial, and add a small and steep as required bump function near 1/4 to make the equation true while not displacing it too much. You can easily formalize this if you are not a complete brainlet.

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Why do you think mainstream """scientist""" refused to allow for this to be called the aether?


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The long explanation(s)/proof(s)

the archive(s)

>NULL result
Sure, but it was refined and performed again some time ago.
read this you dolt
>you won't though
exquisite bait

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how can the 3b1bniggers ever recover

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