[a / b / c / d / e / f / g / gif / h / hr / k / m / o / p / r / s / t / u / v / vg / vr / w / wg] [i / ic] [r9k] [s4s] [vip] [cm / hm / lgbt / y] [3 / aco / adv / an / asp / biz / cgl / ck / co / diy / fa / fit / gd / hc / his / int / jp / lit / mlp / mu / n / news / out / po / pol / qst / sci / soc / sp / tg / toy / trv / tv / vp / wsg / wsr / x] [Settings] [Home]
Board
Settings Home
/sci/ - Science & Math


Name
Options
Subject
Comment
Verification
4chan Pass users can bypass this verification. [Learn More] [Login]
File
  • Please read the Rules and FAQ before posting.
  • Use with [math] tags for inline and [eqn] tags for block equations.
  • Right-click equations to view the source.

10/04/16New board for 4chan Pass users: /vip/ - Very Important Posts
06/20/16New 4chan Banner Contest with a chance to win a 4chan Pass! See the contest page for details.
05/08/16Janitor acceptance emails will be sent out over the coming weeks. Make sure to check your spam box!
[Hide] [Show All]


[Catalog] [Archive]

File: sciguide.jpg (9 KB, 200x140)
9 KB
9 KB JPG
https://sites.google.com/site/scienceandmathguide/
>>
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.

You are given the chance to time travel to the future once at any interval you want.

How far would you go and why?
17 replies omitted. Click here to view.
>>
bump
>>
>>8602164
Personally? I'd talk to Simon. He keeps introducing himself but nobody wants to communicate with him. Just control him.

He seems like an alright... entity?

Fucked if I know mate. Feels like 2016 was bracing us for hyper-weird shit.
>>
>>8605919
simon?
>>
>>8602164
I would go two million years into the future so I would die instantly
>>
File: pepepicaso.jpg (20 KB, 502x460)
20 KB
20 KB JPG
>>8602164
I'd probably shoot for about 200 years. Not an enormous amount, but if tech progress remains steady, there should be plenty of toys and scientific breakthroughs to keep me interested.

Really though, I'd much rather just go back to my childhood, and do things over again. I'd give the future for the chance at that.

File: problem.png (27 KB, 1252x1504)
27 KB
27 KB PNG
Inspired by the latest bout of probabilityposting, I'd like to pose a challenge which generalizes problems of boxes and balls.

Selecting randomly from n boxes, each of which contains some number of balls of m different colors, what is the best way to determine which box you selected, making sequential draws and given full information about what all of the boxes contains?

File: photo.jpg (116 KB, 900x900)
116 KB
116 KB JPG
Is he, dare I say it, "our" guy?
13 replies and 1 image omitted. Click here to view.
>>
>>8607035
I may have jumped the gun calling something retarded without even thinking of something like that, Dunning-Kruger effect at work I suppose. Why aren't there rules about avoiding square rooting a potentially irrational number like there are with dividing by 0 then? Or is that expected to be taught in school soon enough?
>>
>>8607004
it is obviously fake nigga. like are u autistic or smthn
>>
>>8607058
why does everyone bully /x/ on this board

/x/ and /sci/ are my two most browsed boards
>>
>>8607092
>Why aren't there rules about avoiding square rooting a potentially irrational number like there are with dividing by 0 then?

Because in usual analysis we work inside a weird set called the real numbers.

In this set, by the way it is defined, every infinite decimal can exist. If you care about why this is then look up dedekind cuts.

This form of thought is very interesting but it is also lacking. Dedekind cuts are such a deep logical concept that they are completely removed from any number theoretical/computational need for mathematicians. Which is why it makes sense to re-write applied mathematics and number theory in terms of rational numbers.

Dedekind cuts and real numbers are good pure logic, but bad mathematics.

>>8607092
>Or is that expected to be taught in school soon enough?

If you study pure mathematics then at some point the real numbers will be rigorously defined. But the knowledge you need to understand them is so huge that I never think such a class will ever be taught in schools.
>>
>>8607098
Paranormal activity is not backed by evidence but rather by faith, it's the antithesis of science.

File: Capture.png (9 KB, 297x302)
9 KB
9 KB PNG
Previous thread: >>8591198

Post all your stupid questions that don't deserve their own thread here.

I'm trying to find two compact connected surfaces that are not homotopy equivalent but become homotopy equivalent after removing one point from each.

https://en.wikipedia.org/wiki/Surface_(topology)#Classification_of_closed_surfaces
says there's only the homeomorphism classes of the sphere, the connected sum of g-tori and connected sums of real projective planes

A sphere minus a point is homotopic to a point and a torus minus a point is homotopic to a figure eight, but what does a real projective plane minus a point look like?
20 replies and 8 images omitted. Click here to view.
>>
>>8606764
There's still some stuff that I wanted to clear up. I got a great bigger picture of what I'm dealing with but I want to be sure of the smaller things.
If you're that anon then thanks a lot for your help before.
>>
Anyone here writes scientific papers? I'm not a native english speaker, which of the following formatting is correct?

>It was demonstrated in 2015 (Luc and Wolf 2015).

or

>It was demonstrated in 2015. (Luc and Wolf 2015).

Should I place a dot after the first occurrence of 2015? This is the end of sentence, and the reference is only in relation to the sentence.
>>
Reposting from previous thread (Not OP but I just can't seem to solve this):

>>8596114
"just looking for a hint, not a solution

given a continuous function f from the unit sphere embedded in R^3 to R, show there exists an orthonormal basis u1,u2,u3 of R^3 with f(u1)=f(u2)=f(u3)

i can do it when its a function f(theta):[0,2pi] to R from the unit circle in R^2 instead of the sphere in R^3 but i don't know if the proof is adaptable.

an orthonormal basis u1, u2 in R^2 has a pi/2 angle between them so we can consider the function f(theta)-f(theta+pi/2)

since the circle is compact f has a maximum u and a minimum v

these satisfy f(u)-f(u+pi/2)>0 and f(v)-f(v+pi/2)<0, so by continuity there exists w with f(w)-f(w+pi/2)=0 and so the vectors corresponding to w and w+pi/4 are an orthonormal basis of R^2"
>>
>>8607087
I was the one who replied to you. What I don't understand is if you should prove the statement for ALL functions or just that there EXISTS one such function.
>>
>>8607096
I'm not the anon who originally posted that question. Proving that such a function exists is trivial (let f be constant), so I'm assuming the OP meant that it's supposed to be proved for all continuous functions

File: IlW8Mkp.jpg (2.82 MB, 3072x2038)
2.82 MB
2.82 MB JPG
What would a space warship using real non-fictional technology be armed with?
66 replies and 7 images omitted. Click here to view.
>>
>>8607034
>>8605135
this game looks great but i'm too fucking retarded to play it.

can a person who can only do basic arithmetic play this, or do you need algebraic skill?
>>
>>8607055
what happens if i have a ham sandwich with extra mustard on the ISS? do the air filters filter out my ass particulates?
>>
>>8607056
If you can play Kerbal, you can play ChoDE.
>>
File: best mustard.jpg (81 KB, 500x500)
81 KB
81 KB JPG
>>8607059
I'm pretty sure Russians love mustard and anyone who doesn't like mustard doesn't deserve to be an astronaut.
>>
File: screenshot328.png (456 KB, 1280x800)
456 KB
456 KB PNG
>>8607061
>If you can play Kerbal, you can play ChoDE.

OMG I LOVE KERBAL!

What does the future hold in store for life on earth?
>>
Pic related
>>
probably some cool stuff too bad we won't be around to see it.
>>
File: Animals_of_the_future.jpg (139 KB, 1220x1030)
139 KB
139 KB JPG
Bump.
>>
>>8606017
>Implying evolution exists

File: TI-92_PLUS_ZOOM.jpg (433 KB, 1338x760)
433 KB
433 KB JPG
ITT: Your favorite calculator.

Pic related, it's mine.
38 replies and 8 images omitted. Click here to view.
>>
>>8603631
Multiplying ma 6x6 matrices mechanically
>>
>>8606275
It's absolutely pleb tier, especially since way more capable alternatives exist that are completely free. Also you should seriously consider to start thinking about what you want to waste your time with. Is it really worth learning to use some obscure, very limited tool that you'll never use ever again? Or isn't it more useful to learn about a tool that looks great on your CV and actually opens up a whole range of possibilities.
>>
>>>8603654
>Are those as easy to use as people say?

Yeah, you have no idea how many times it's saved my ass in tests.

Does everything from simplification to complex solving and can express in every form. Allows you to assign matrices by letters and do advanced problems, even has visual vector functions. Worth every penny
>>
>>8603984
>That is just fucking retarded. You can get a chink tablet for the same price or cheaper and you'll have far more screen + lots of different functions and internet.


Uhuh, yeah I'm going to stick with my "I can check my answers in 2 seconds" calculator that costs $200, over your "second grade tablet that might explode and can't bring into the exam hall"
>>
>>8603631
>>8603654
>>8606253
>>8606278

>d/dx 2017x
>falling for the graphing calculator meme

File: 1483959826659.jpg (30 KB, 600x600)
30 KB
30 KB JPG
CS kek here reminding every If you don't know any sorting algorithms, object orientated programming, and have a Mac, you're a retarded fag.
3 replies and 2 images omitted. Click here to view.
>>
>>8606202
i program in haskell because functional code is objectively cleaner and produces less bugs btfo
>>
>>8606376
this
>>
>>8606202
Not knowing OOP is a good thing.
>>
>>8606425
It's like he's retarded. I bet he also thinks GC is the best part about Java.
>>
>>8606202
>CS
>Shitting on OS X

You have some learning to do.

File: 1484382714246.jpg (868 KB, 1280x1280)
868 KB
868 KB JPG
Engineers and computer scientists can code programs for fun or play with electronics in their spare time but what can I, as a biochemistry student, do as a hobby?
7 replies omitted. Click here to view.
>>
>>8606100
Nothing experimental. You just have to learn to code as well I guess.
>>
>>8606100
Make recreational drugs i suppose.
>>
>>8606100

kek.

You can learn to code so you can work on desiging new molecules via computer simulations.
>>
>>8606100
You could shitpost on /sci/ like other biochems.
>>
You could learn to cook ?


Cooking is a very useful skill.

>How big of a problem is AMR gonna be in the near future?

>How can we stop it?

>Is it too late?

File: john von neumann.jpg (72 KB, 433x614)
72 KB
72 KB JPG
His genius was unprecedented
84 replies and 8 images omitted. Click here to view.
>>
>>8606008

Try to write a play with the same poetic quality of Shakespeare. It can be a 1 act only play. I dare you.

You can write anything and call it poetry, and so any retard can be a poet. Now, to write something that is much greater in its verbal texture and imagistic beauty than all the other works of mankind in the field of words, that is the real deal.
>>
>>8606795
/go to lit or fashion you imbecile art faggot
>>
>>8606835

Says the guy who loves "muh movies", and "muh songs".

As if you could live happily only with math. Imagine a world without your Star Wars or your Marvel heroes or your Green Day or your Metalica.

Yeah, in the end of the day art matters to everyone, even people like you. And in the real of art figures like Shakespeare, Beethoven, Mozart, Bach and Michelangelo are the greatest.

And btw, Newton, Einstein, Gauss are all far superior to Jancsi.

But let me give you a gift after this sour post. Here: take a look at Newton's originals manuscripst from his student days:

http://cudl.lib.cam.ac.uk/view/MS-ADD-03996/1
>>
>>8606880
>As if you could live happily only with math. Imagine a world without your Star Wars or your Marvel heroes or your Green Day or your Metalica.

Dont forget his Harry Potter
>>
>>8606880
>implying math isn't art

File: mqdefault.jpg (8 KB, 549x171)
8 KB
8 KB JPG
Sometimes I lurk this board just to look for MIT/Caltech anons and ask them how the hell they got in
107 replies and 5 images omitted. Click here to view.
>>
>>8606830
Anyone? I'm guessing I'm just fucked.
>>
>>8606946

yeah, probably...

But most of us are, anon
>>
>>8606931
I am not that anon and I do not deny that their life is harder assuming they are poor however their hardships in that sense don't have to do with the color of their skin but the money in their bank account.

The middle class kid and the poor kid both have a shot, and a similar shot considering they can both get A's through hard work, as high school classes can really be overcome through a good work ethic in most cases and just not dicking around constantly. The poor kid is at a genuine disadvantage when it comes to ACT/SAT because they cannot afford tutoring, which could be solved through every public high school having a person who's job it is to teach the kids how to do well on those tests, or at least directly teach them whats on the test.

Now both of our posts haven't directly referenced the race of the middle class kid and the poor kid, although it is implied. The true shit of affirmative action is that that poor kid who has lived in crime and sorrow could be white and the middle class family could be black. There are verifiably a shitton of poor whites, and also a shitton of middle class or better blacks. The black kid gets a better shot at an Ivy despite having none of the disadvantages.
>>
>>8607071
>>8606931
also don't mistake that I am advocating for affirmative action on wealth rather than race. I believe that it simply shouldn't exist. A better way would be to try to give the poor the resources (for example every public school having a person to teach the ACT/SAT, maybe just have the guidance consolers do that)
>>
>>8607071
It is true that poor whites also need help from affirmative action and that is maybe one of the failures of the problem. Hopefully, as more rich black people appear politicians will realize that race-based aid is no longer needed and we can go back to the old days of wealth-based aid.

I agree.

But that guy who had a FUCKING TELESCOPE is not poor. So I have no sympathy for him. I have a telescope myself and they go for hundreds of dollars. That is not an expense a poor kid can afford. So fuck him.

> I believe that it simply shouldn't exist.

Then we will have to disagree. Poor people need the help.

>A better way would be to try to give the poor the resources

Good idea. Lets give them the resource of easy access to top tier higher education. That sounds like a good resource.

Glad we could agree on something.

File: god_of_gaps.png (15 KB, 993x826)
15 KB
15 KB PNG
Geometry disproven.
21 replies and 4 images omitted. Click here to view.
>>
>>8606921
top kek
>>
File: Untitled.png (12 KB, 956x378)
12 KB
12 KB PNG
>>8606654
>>
>>8606726
Once never seen a worse bullshit in my life
>>
>>8607013
I delete this
>>
>>8606726
Nice try samefag op

File: 1452938763200.jpg (129 KB, 701x576)
129 KB
129 KB JPG
Is anyone here RETARDED enough to believe the probability is 50/50?
162 replies and 25 images omitted. Click here to view.
>>
File: goldball fucking shits.png (53 KB, 1861x817)
53 KB
53 KB PNG
Guys, please.
>>
>>8603718
the probability is you will pick the silver one anon because you're one unlucky bastard
>>
>>8605356
This is just wrong on so many levels. Mainly the fact that he divides by n in the end. Should be goldenballchosen/(silverballchosen+goldenballchosen) since the fact that the first ball was golden is a condition.
>>
>>8605547
Bet all your money since you have 1/2 chance of winning the bet and the expected value of betting x amount is 1.5x+100000
>>
>>8607082
Woops, that should be 0.5x+100000



Delete Post: [File Only] Style:
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
[Disable Mobile View / Use Desktop Site]

[Enable Mobile View / Use Mobile Site]

All trademarks and copyrights on this page are owned by their respective parties. Images uploaded are the responsibility of the Poster. Comments are owned by the Poster.