/sqt/ - Stupid Question Thread: Linguistics Edition

>>8773374
Why isn't /sqt/ a sticky?

But more importantly, I'm looking for THE authoritative text in "discrete math". Whatever that means. Why don't I hear more talk of it here on /sci/? Proofs are cool, digital logic is fun, etc.

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>>8773444
There's rarely a single authoritative text for any field, but Stanley's 2 volumes are certainly classics

>>8773374
Apparently I suck at math.
I have a system with four states, and two state estimators and I'm trying to construct a hidden markov models.
My observations though, are already belief states (probabilities over each state), that is, in the form: [0.1, 0.6, 0.2, 0.1]
What I want to combine is two of those observations, together with a transition matrix (4x4). I can only find HMM literature where the evidence is a single binary observation.
Anyone care to point me in the right direction? What am I missing? Proper book?

Thanks

>>8773451
Thank you. And yeah I was kinda just seeking whatever this board circle jerks over (like Spivak's for calc). Being that discrete math is such a broad (and less popular) topic I can see why there wouldn't be a meme-spammed book about it here.

Haven't really explored "Enumerative Combinatorics" but reading up on it sounds fun. Ty anon-san :3

I was looking at some high speed video of a cloud chamber in action (can't post the video, it was for a commercial project). Considering the speed of the particles, I was expecting to see the entire length of the vapour trail form instantly, even at 10kfps but, weirdly, the heavier trails actually form from the end furthest from the source and travel backwards towards it. Any ideas why this might be happening? I'm a biochemist by trade but have been helping with this project because it required a modification to the cloud chamber and I'm the departmental 3D printing guy.

Can someone help me wrap my head around Taylor Series?

Despite watching Khan, PatrickJMT and carefully reading the text I'm still not solid on it. I can mechanically complete an exercise, but the conceptual understanding lags behind. At any rate, my methods will work after a few more rinse-and-repeat cycles and good nights sleep, I just want to expedite the process a little bit. What are some of it's applications?

>>8773804
it kind of makes the function that you're computing the taylor series of easier to handle. Because if your taylor series converges you can work with a quite easy algebraic object instead of the function that you started with. also, if a taylor series converges to its function you know that you're function is infinitely many times differentiable (also called "smooth")
don't know what exactly you're struggling with, but i remember when i started learning about taylor series i didn't get the point either at first. maybe you should just look at a couple more examples?

>>8773804

convert a function to polynomial iirc

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What level of math do I need to be at to understand Fourier series? I'm interested in crystallography and sound synthesis.

Fuck I should've just majored in physics instead of chemistry where they don't require any rigorous math at my school.

>>8773890
I think its mostly infinite sums with some calculus, but I'm not sure

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What are prereqs for Real Analysis? Trying to form a sort of math roadmap.

>>8773374
>Are some languages harder to lip read? If so which is hardest?

Any language that heavily features sounds not associated with the lips (e.g. tones, nasalization) would probably be really hard to lip read.

Let's say I wanted to get the percentiles of a data set A={1, 2, 3, 4, 5}. If I wanted to get the percentiles of B, the set containing n duplicates of each element in A, would I get the same results?

>>8774013
The same percentiles for B as for A, to clarify

Why do we allow scientists to create new strains of viruses and other dangerous diseases in labs? They may be safe but what if something horrible was made and accidentally or intentionally leaked? How are new diseases created in labs and how do they form naturally? Could a breakout of a deadly disease make humans go extinct in the modern world?

>>8773374

What is the abstract algebra classification for a polynomial with negative exponents?

for example

[math]\frac{(x+2)^4}{(x+3)^5}[/math]

I'm ready to be raped with abstract algebra words I don't understand

>>8774052
What you posted is called a rational expression.

>>8774052
https://en.wikipedia.org/wiki/Rational_function

>>8774052
>I'm ready to be raped with abstract algebra words I don't understand
>>8774082
>>8774134
I love it

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Quantum Question Normalising Wave function

>pic related

How do i do part (a), studying for exams and i got stuck. I know Ill have to multiply the wavefunction by its complex conjugate and integrate over all space but what do i do with the integral he gave me in the question thats = D? Pretty confused, help would be appreciated

>>8774425
Wait i didnt even begin the question now that ive wrote down the first step its p obvious i need to substitute int psy^2 with D. oof think I might have it, sorry for wasting time lads

If you put a live wire or some other source of electricity into water that's flowing, does the charge get carried along in the same direction as the water? Or can it travel upstream?

>>8773444
Aigner - Combinatorial Theory

Not sure how authoritative it is, but it really tried to give a relatively general framework for combinatorics (that being said, combinatorics is pretty diverse and "horizontal" in nature so I don't think there'll ever be a definitive text)

>>8774468
The speed of electricity in salt water is just over 0.1c, from the PoV of the electricity, the water is stationary.

>>8774503
Thanks senpai. If you had some super hard water jet, would you be able to get the electricity to travel down stream, or is getting water to go at those speeds unfeasible?

Does this also mean you could put a wire in the spray from something like a hose or riot cannon and shock people from long distance?

>>8774517
>Electrified squirt guns when

>>8774517
>is getting water to go at those speeds unfeasible
Yes, getting a stream of water to 10% of the speed of light is pretty unfeasible, it wouldn't be a so much a stream of water as it would be an unstoppable destructive force. That would be 33k times faster than a water cutting jet, requiring over a billion times the energy.

>Does this also mean you could put a wire in the spray from something like a hose or riot cannon and shock people from long distance?

Water jet based electrostun devices have been a dream of police and military forces for a long time but it's actually very hard to create a solid stream of water that travels over long distances and, if it were possible, you'd have to have a complex control system because initially it would put a potential difference across the target of that between the stream and earth but, as soon as the target got wet enough for there to be a continuous wash of water from the jet impacting the target to the ground they'd only experience a voltage of the PD within the stream for that distance.

In short, you'd either have a stream that would kill them on contact and mildly shock them after stream-ground contact is made or a non-lethal incapacitating shock for a fraction of a second followed by something as effective as a non-Joker joy buzzer.

>>8774551
Oh shit, I'm a brainlet, I didn't realise by c you meant speed of light.

Ah well, time to rig up an electrified water gun and go around zapping people.

>>8774560
I'll check the obituaries about a week from now.

>>8774570
Or you could check the super hero list for cool people who have electric super powers

>>8774625
Link?

>inb4 Area 51 database

Finishing core classes and finally getting into my science classes.

Want to major in biochemistry or cellular biology and would like some books that I can read on the topic as well as books I can read about preparing for majoring in STEM.

I'm specifically not looking for text books, though

>>8774686
bump. I'm thinking about switching to some kind of engineering or applied mathematics and I'd also like to get a feel for what I'm getting myself into.

>>8773374
>Are some languages harder to lip read?
Yes, any form of sign language is impossible to lip[ read.

Is there a biological explanation for why dicks become so sensitive to any contact after ejaculation?

So something I used to do a long time ago in middle school is think that any sequence of numbers with an unknown pattern could eventually be reduced to a sequence of ratios between the terms. Then if those ratios don't form a clear pattern, you could get the ratios of THOSE ratios, repeating until it was reduced to a clear pattern.

Obviously this doesn't (always) work, but I suspect that this is an actual thing and I want to know the name of it.

I have a question about the relationship between current flow and electron drift in an electric circuit.

I know that both phenomena occur, and that the electron drift occurs in the opposite direction of the current flow.

But my question is this: Does the amount of current flow EXACTLY determines the corresponding amount of electron drift? Or can there be some variation between the two?

In other words, does 1 C/s of current flow necessarily demand that exactly -1 C/s "worth" of electron drift is also occurring? (I use the word "worth" here to mean that I count each electron that drifts by the selected point as representing -e amount of charge.)

My physics textbook doesn't make this very clear....

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I'm not understanding very well what has been done in the pic related.

I get the second parenthesis in the first member of the equation was multiplied by 1 (4/4 = 1) and then what? Does this trick has a name? Where could I find more about it?

>>8775153
The 4 in the numerator was distributed. Then both sides were multiplied by 4 ; canceling out the 4 in the denominator and changing 10 to 40.

>>8775153

First, simplify just the numerator (ignoring the denominator for now). Do this by multiplying the 4 into (15x^2+8x+1) to get (60x^2+32x+4) in the numerator.

Once you're done with that, notice that you still have a 4 remaining in the denominator.

So simply multiply both sides of the equation by 4 to "get rid" of that 4 in the denominator.

>>8773934
What have you done so far?

>>8775187
Forgive me for my dumbness in advance.

I understand the 4 in the numerator was distributed and that both sides was multiplied by 4 to cancel out the 4 in the denominator of the first member of the equation but I keep looking to this and thinking "there's something wrong".
Shouldn't I multiply both parenthesis each for 1 or 4/4? Is it even, lets say, "allowed" to be done only in the second parenthesis? I'm really confused about it, my basic math is completely rusty

Thank you

>>8774439
[math]\psi^2[/math] won't integrate to D, though, and that value of [math]\psi^2[/math] isn't important for this question..

Quick question about Fourier transforms. When I transform the equation [math]u_{t} = \frac{1}{4}u_{xx}[/math], that means I only take it respective to [math]x[/math] and treat the other variables constant right? That would give me [math]\hat{u_t} = -\frac{1}{4}k^2\hat{u}[/math]

>>8775241
It might help if you use variables to represent all the complicated stuff.

Your equation is basically this:

A(4B/4) = 10

.. where A and B are the two polynomials.

Right away, it's clear that the 4s cancel, giving you this:

AB = 10

However, your second equation has 40 on the right side, not 10. To mirror this, you need to multiply both sides of the equation by 4:

4AB = 40

The nice thing about multiplying 4 times A times B is that you can do them in any order.
Therefore, all of these equations are identical:

4AB = 40
4(AB) = 40
(4A)B = 40
A(4B) = 40

Well, as it turns out, the second equation in your pic chooses to leave A alone, and to multiply 4 by B, so your case is this one:

A(4B) = 40

Now, let's plug in the actual polynomials for A and B:

(60x^2+32x+1) ( 4 (15x^2+8x+1) ) = 40

Multiplying the second parentheses out, we get exactly the second equation in your pic.

>>8775211
Thank you

>>8775325
Ohhhh, now I got it! Wow, I'm so fucking stupid!

So if I have n parenthesis = x, being algebraic expressions what's within the parenthesis and x belonging to the integers higher than 1, I could multiply and divide only one of those parenthesis, distribute the number in the numerator to the respective parenthesis then multiply both members by the number that would cancel out the number in the denominator and I would keep the equality? Awesome!

Even though it was so obvious, I really appreciate the time you took to type this in order to help me understand what happened, thank you!

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This is a graph of elevator motion. Why isn't it symmetrical? Why doesn't the elevator go down in the reverse way it goes up?

>>8775647
It think you appreciate the gravity of the situation.

>>8775660
Isn't it mechanical action that lowers the lift?

>>8775290
Yes

>>8775647
Idk lol I guess it gives a more uniform G force.

>>8773934

You're going to want to read up on predicate logic and set theory. Get comfortable with quantifiers and their proofs. I've was going to write a whole thing where I gave an overview of why you should start with propositional logic then transition into predicate logic and then set theory, but I forgot about domains and understated the importance of set theory, which are both important and these lecture notes are better than what I could write out anyway.

https://www.cs.utexas.edu/~schrum2/cs301k/lec/topic04-predicateLogic.pdf

I'm sure if you're interested in real analysis you're probably already familiar with propositional logic so that was another reason I omitted it. There's plenty of info out there with all the definitions you need. If you use this search format in google: "[insert subject] .pdf site:.edu" you can find lecture notes on almost any subject.

Good luck.

What do engineers really do? Make stuff in CAD all day?

>>8776046
I sit in MATLAB all day fixing shitty code, that I could have probably rewritten better and cleaner in C.

Does [math]a+a\bigg(\sum\limits_{n=1}^{\infty}(b-ab)^n\bigg)[/math] simplify to [math]\dfrac{a}{b-ab}[/math]?

I was just trying to solve some dice probabilities and ended up learning about infinite series(and LaTeX just to make this post), but then I realized I didn't need to use an infinite series.

>>8773374
Mohawk has no labial consonants other than "w". So I imagine it would be hard to lip read.

How the fuck do you sing in Chinese?
I mean, the tone of the syllable carries some of the meaning of the syllable, right? So does the tune have to fit exactly what the words are? But the words are random wrt tones, and Chinese music doesn't sound random.

>>8773374
very clearly NOT a fucking koala you mongoloid

>>8776101
>http://www.wolframalpha.com/input/?i=a%2Ba+sum(n%3D1+to+infinity)+(b-ab)%5En
Nah. Also, it's just a geometric series, you should be able to find its closed form.
Also, use "\left(" and "\right)", usually better than "\bigg"

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>>8776023
Thank you anon

>>8776153
I realized where I fucked up some time after posting, but I didn't work out the solution. How does wolfram decide how to format its outputs? Because I'm pretty sure [math](a-1)b+1[/math] isn't a correct way to write that.

My next question is, is this particular formula used for anything outside of this obscure dice game?

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>>8773374
Would you solve this using a similar thing to the method usually shown to show that the naturals are as numerous as the integers?

>>8776298
I don't even get the question, isn't that already in the definition of even?

>>8776298
>>8776303
Oh shit, I didn't even see the even part. I guess it is.
So for the 'infinite' part could we just add any number of +1-1s?

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Not a troll

Legitimately; how does one solve this question?

>>8773374
How does Google Translate work, step by step.

What tech and methods are employed?

Are there series that converge when their variable is set to 1, but diverge if the variable is set to even an infinitesimal amount above 1? In other words, series that can achieve a state of being "on the verge of infinity".

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How do I write cheat sheets in [math]\LaTeX[/math]?

>>8773890

Calculus II

>>8776118
You can spend too much effort trying to synchronize tone and melody, or you can disregard tone altogether as it will still be understood to a certain extent given its context.

If I have a differential equation

[math]u'' - e^{t}u'-e^{t}u=1[/math]

For which I want to find a general solution, I can start by solving the homogenous equation - in order to do this, I can use the characteristic polynomial or equivalently translate the homogenous equation to a two dimensional system which gives a 2x2 matrix of which I would need to find the eigenvalues. This would give me two eigenvalues as functions of t,

[math]\lambda_{1,2}(t)[/math]

And I can use these to determine the eigenvectors, combining these to construct the fundamental matrix. From there on its easy sailing. My question is, the eigenvalues of a matrix equation with variable coefficients look nasty. Is there a way to find a prettier solution?

Is there some convenient place i can download solution manuals for textbooks without paying?

>>8776319
Its the same kind of problem as those "fence in the cows" ones from the SAT or whatever. Just come up with an equation which describes the relationship of all the parts, then reduce and minimize.

>>8776867
Libgen

Can anybody give me a microscopic explanation on how lenses converge and diverge light?

Does cyclic homology require a unitary ring, or can it be a commutative non-unitary one?

is the inverse of a function always bijective?

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>>8776795
Google "LaTeX cheat sheet templates"
and start learning more about your favorite markup language.

>>8777146
No, consider a function that maps 1 to 0, 2 to 0. Is the inverse bijective? In fact, what is the inverse?

>>8777168
obviously he was assuming an inverse exists brainlet, he's not asking about non-existent functions

>>8777174
Check retraction and section, the one-sided inverses

>>8777194
you really think of one-sided inverses when someone says inverses?

he said 'the inverse' so it's presumably unique, unlike retractions or sections

>>8773890
best way to approach it is through algebra. Fourier analysis is just projecting function onto bases of some periodic functions.

You need to understand some bits of integration.

>>8777174
>brainlet
Are you taking your frustrations out on me? Go do that somewhere else.

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>>8777213
what frustrations?

>>8777201
No, I don't think of those. Nevertheless, there is a reason for the notion of mutual inverses. If the one posting the function used 1 or 2 instead of 0, he'd have a retraction

>>8777168
>is the inverse of a function always bijective?
>no, because look at this irrelevant example which isn't a non-bijective inverse of a function

what's the biggest reason why your surroundings sound so much louder than usual sometimes? the weather seems to be windy when/before it occurs. the most common explanations are retarded and/or don't apply to my circumstances.

can't it just be the air pressure? you know how water travels better in water, through the ground, or why not the classical example of train tracks, where you can put your ear against the rail to hear a train coming from a mile away. higher air pressure = higher air density = sound travels better through the air = surroundings sound louder?

>>8777255
>you know how water travels better in water
*you know how sound travels better in water

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What's wrong with his head

>>8777366
https://en.wikipedia.org/wiki/Cutis_verticis_gyrata

>>8777366
eww he should let his hair grow a bit to cover that shit up

>>8777391
must be really painful if he gets ingrown hairs from that though

>>8777163
Thanks, I didn't think of that. I assumed googling LaTeX cheat sheet would just throw a bunch of LaTeX commands compilations.
Guess I should trust my favourite browser more.

I could also break my question up in smaller pieces: what I actually wanted to know was
>how to make colourful boxes and put text in them like you do in many cheat sheets
>how to avoid shit like on pdf related: equations being misaligned and going half way through the margin, the whole thing taking much more space than it should, ridiculously big spaces between the math and the text
>some nice font to chose, that would also cover my language's special snowflake letters (and perhaps other languages too, for names'n'shit)

>Corrupted file or unsupported file type.
wtf fourchan?
http://docdro.id/oTc7l1X

Since I'm posting my pdf anyways, could someone check for any typesetting mistakes I made (I know there's plenty but I may not be aware of all of them) and how I can fix them? Thanks.

If I use the interpolation function in MATLAB on a data set. How do I find the error of the results?

>>8773374
what is the bigger picture concerning arc sine, arc cosine, and arc tangent?

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how do you calculate the trajectory of a projectile while taking into account the air resistance? assuming you have measured/estimated the drag coefficient and mass

I'm probably just retarded, but is there a specific term for the type of value that gets assigned to divergent series? Because it's equal in a sense, but it's not really a sum.

>>8777485
if you have the bigger picture of sin/cos/tan, then the inverse (arcsin/arccos/arctan) is just the corresponding angle

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Algebraic brainlet here, please explain how I'm supposed to get the second line from the first.

>>8777673
Did you forget about reciprocals?

>>8777673
take out the 6 from the parentheses

move the n^3 into the parantheses

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I'm not that sure about that question
>pic related

Somewhat related.

Me and a friend are being accused of plagiarism. He started the assignment after the deadline and after I uploaded it and needed help, so I showed him mine and explained how to do the subjects (i.e. teaching her the fucking course content).

Apparently he copied my work cause the system picked it up and they're very fucking similar.
I'm in the clear if I can prove it's my original work right? Or am I in the wrong for showing her mine?

>>8776198
>How does wolfram decide how to format its outputs? Because I'm pretty sure [math](a−1)b+1[/math] isn't a correct way
I mean, correct/incorrect? Who's to say?
I think it decided that [math]b[/math] takes precedence over [math]a[/math], so it grouped things according to orders of [math]b[/math] (ie [math]()b^0+()b^1+()b^2+\ldots{}[/math]).
But that's just a guess.

>is this particular formula used for anything outside of this obscure dice game?
I dunno. Which dice game are you talking about?

>>8777784
>Or am I in the wrong for showing her mine?
Yes. This is called collusion, and is often treated as severely or nearly as severely as plagiarism. It's surprising that you never received any documents explaining what plagiarism and collusion are, and the consequences, because presumably you wouldn't be retarded enough to do what you did after reading such documents.

So the upload dates will presumably prove that he plagiarised and you colluded, rather than vice versa- but that won't save you. The best you can hope for is a zero mark on the assignment; in the worst case you could be expelled from your university.

Since they have absolute evidence, it would be stupid to deny it. Confess, apologise profusely, and hope a zero mark is the only penalty they impose.

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>>8777673
I went step by step so you could understand. You can do the whole process in your head quite easily desu

>>8777829
A die with win probability [math]a[/math] and a die with win probability [math]b[/math] are tossed. If [math]a[/math] loses but [math]b[/math] wins, both are retossed. This repeats until at least [math]a[/math] wins or both [math]a[/math] and [math]b[/math] lose at the same time. The probability of it resolving on a winstate for [math]a[/math] is the previously discussed formula. So I'm asking, are there other real life situations where one probability is adjusted based on another probability in this specific way?

>>8777838
Thanks anon! That makes perfect sense now, but it simply didn't occur to me for whatever reason. Looks like I'll just need to practice a bunch more.

>>8777831
I'm not intending to lie or anything. And he said he'll tell the truth as well i.e. he didn't copy my work and was just taught the subjects so he could actually do the work.

It's annoying because he explicitly said "Oh I won't just copy you, I'll reword it" but all he did was move the words around in the sentence, and sometimes not at all.

>>8777701
The answer is yes to all of them;
f must be bijective since it has an inverse g.
and g must be bijective since it has an inverse f

>>8777880
>he'll tell the truth as well i.e. he didn't copy my work
>all he did was move the words around in the sentence, and sometimes not at all
It would seem that he did in fact copy your work, no? It seems likely to me that he entirely ignored your teachings (or just still didn't grasp the concept) and decided to just use yours.

>>8777908
That seems to be the case.
He's still insisting he didn't copy and arguing "How else can I word this?" when it literally uses the same sentence structure and keywords.

It's still my first year so I hope the worst I get is 0 on this assignment, but the emails aid "0 mark, no re submission, for each coursework" so I don't know if that will be the case after I explain the reasonable situation.

Someone explain the American undergrad/grad/post-grad system to me?

In my country it works like this

"Professional" bachelor (3 years)
--> Job market


"academic" bachelor (3 years) (much harder than professional bachelors )
--> Job market (not many people do this)
OR
--> a master degree (2 years)

hello friends,

prove using bezut theorem that


>If a, b, and c are positive integers such that gcd(a, b) = 1 and a | bc, then a | c.

im gonna try, since we a | bc, then a | tbc for any t E Z, then we have a | sac, therefore a | sac + tbc and since tbc + sac = c, then a | c.

motherfucker is this seriously trivial for pros?

>>8778035
>im gonna try, since we a | bc, then a | tbc for any t E Z, then we have a | sac, therefore a | sac + tbc and since tbc + sac = c, then a | c.
this is wrong, you never showed c=ak for some k

and yes its trivial

>>8778035
you also didnt use bezouts theorem brainlet

>>8778067

why would i need to show that? i already show that a | (tbc + sac) and since i know that tbc + sac = c, so a | c

>not using bezout theorem

sry for the being retards but

> gcd(a,b) = 1
>then by bezout theorem we have sa + tb = 1

from a yotutube comment:

>There's another solution as well which is to only use the minimum number of legs required for stability in the dimension you're working on, which is (N+1) where N is the number of dimensions of your surface.
>If you want a table to be stable on a 2d plane (the ground) then you need (2+1) = 3 legs, a 3 legged table can never wobble on a 2d plane, even if that 2d plane is uneven.

referring to this video: https://www.youtube.com/watch?v=OuF-WB7mD6k

explain /sci/ ???

why can't the [math]\sqrt{4}[/math] be [math]\pm 2[/math] but this can happen in an equation like [math](x + 1)^2 = 10 \Leftrightarrow x + 1 = \pm sqrt{10}[/math]?

>>8778252
because the square root function can only have one output if you want it to actually be a function, and so the convention is to take the non-negative root

>>8778265
ty

so if I look for the solutions of a quadratic equation the square root has a different meaning than the square root function?

>>8778282
yes

there's always two real square roots to any non-zero number, but the square root function is specifically defined to give the non-negative square root

>>8778290
got it, ty

sorry for the brainlet quesitons, couldn't figure out how to phrase it adequately for google

in chemistry, what determines what position an element takes? For instance, why is it H20 and not 0H2?

also, what do you call the process of adding and multiplying shit in chemistry? H + 02 ----> H20
that stuff

Basic chemistry course decided not to cover this shit.

>>8773972
Mohawk doesn't have any labials besides w. Plus they have two nasal vowels, which you couldn't lip read in any capacity

>>8773374
Do different languages shape your brain differently?

Like if there were words for certain things in one language but not in another, would that affect your perception of the world as you grow older?

>>8778370
Languages do have some effect on brain development, although your phrasing is so vague I'm not sure if it's what you mean.

For example, people born in countries with tonal languages (e.g. Mandarin Chinese) are several times more likely to develop perfect pitch.

>>8778393
Yea that's about what I meant, interesting.

I watched a video about a tribe in Africa that doesn't have a word for yellow or something of that sort, people were arguing what exactly that means.

>>8777857
>are there other real life situations where one probability is adjusted based on another probability
Definitely. You should check out Bayesian statistics.
>in this specific way
Maybe? I can't think of one off the top of my head, but there are any number of statistics problems, so it's reasonable to think that some of them are going to have the same formula as the one you're working on.
It's fairly common for two "seeming different" problems to have the same solution (or at least the same form of the solution).

are there things that can not be proved but you also can not prove that they can not be proved?

>>8778539
God, for one.

>>8778554
I was thinking moreof scientific hypotheses

say there does not actually exist a proof for or against the rhiemann hypothesis
but you can not prove anything about such a proof

is this nonsense?

>>8778569
https://en.wikipedia.org/wiki/Continuum_hypothesis

My lab is having trouble with running histology assays on some sections due to the tissue being dehydrated. Gill 2 and Eosin are the staining agents being used.

Does anyone have any experience in preventing tissue dehydration for histology? We suspect something with the fixation might be going wrong.

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h-hey, guys...

pls help me understand this bullshit i just cant wrap my fucking brain around this.

why the fuck don't they just that there exist some gdc(a,b,r) = k, for some fucking k. and we know that k is unique for any tuple (a,b,r) because we let 0 <= r < b and a < b < r (so the fucking order of the tuple matters).


or im jjus too stupid for number theory REEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE

>>8778674

sry this is the lemma we are trying to proof

>Let a = bq + r, where a, b, q, and r are integers. Then gcd(a, b) = gcd(b, r).

>>8777592
You use the second law of newton and integrate

I need guidance. What should I know before I can prove:

If [math] p [/math] is an odd prime then [math] p [/math] divides [math] 2^{\frac{p-1}{2}} - 1 [/math] or [math] 2^{\frac{p-1}{2}} + 1 [/math]

Is LaTeX handy for research outside of mathematics and physics? Specifically in biomedical research. Not sure how most of these papers are written.

>>8778773
https://en.wikipedia.org/wiki/Fermat%27s_little_theorem

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>>8773374
How does eukaryotic RNA polymerase know how to transcribe a gene but NOT the corresponding complementary gene on the other strand?

For example, if you had a complementary sequence: (promoter) - START - (gene) - STOP, but this sequence only had the promoter/start codon by 'accident' (i.e. it wasn't 'meant' to be a gene, it just happens to have a promoter/start codon by random mistake due to complementary to the other strand), would it still be transcribed?

>>8778773
>What should I know before I can prove
Division algorithm, Euclidean algorithm, extended Euclidean algorithm, etc.

>>8778784
You are fucking right holy shit. I found this out just after I posted this. I first tried doing the most retarded proof by contradiction attempt in history but then I realized that if I multiply those two things I get [math] 2^{p-1} - 1 [/math] which is always 0 mod p as long as p is not 2.
Thus. p divides the product of the two things, and thus p has divides one or the other.

God damn.

>>8778785
There are many checks other proteins perform within the cell to eliminate unwanted/accidental transcriptions. Of course, they don't always work and that's how you can get a genetic condition, just a shitty mutation.

If there is no stop codon however, the chances of the created protein being functional at all is very low. You would get a fucking huge amino acid chain that would be eliminated almost instantly by cell mechanisms.

>>8778790
Funny enough a proof by using the euclidean algorithm crossed my mind but a path was not immediately obvious so I dropped it. Anyways, I got it senpai >>8778791

>>8778648
well I can make a mental note of it but I am a bit away from being able to understand

>>8778813
You don't need to understand what it is. The guy just linked you to a proposition that is neither true nor false.

This is similar to your case but not exactly right.

There can exist propositions that have truth values but can't be proven right or wrong, but the continuum hypothesis is a case of there being no truth value to begin with.

>>8778401
The term you're looking for is linguistic determinism.

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Could this work?

>>8778824
>There can exist propositions that have truth values but can't be proven right or wrong
but it can still be proved that they are not provable?

>>8779007
No
The electricity has no reason to go through the lightbulb, it will just short right where the plug is exposed.
If the positive and negative each had their own tank, however, I'm not sure. It probably wouldn't work well, if at all.

If you multiply two infinite series together, how do you get a product that is also an infinite series?

>>8779122
(sum a_i)(sum b_j)=sum a_ib_j

>>8779007
if the light bulb is tiny

5:30

https://www.youtube.com/watch?v=zlxrPHEJyBA

>>8774051
#1 To enhance the field of pathology.
#2 A lot of people would die depending on how quickly and effectively the area was quarantined.
#3. They are grown in Petri dishes. They evolve.
#4 Unlikely as even the most virulent lab-made pathogens have ~ 90% mortality rate.

>>8779126
This is a lie.
>>8779122
Look up Cauchy product. There's a good treatment of it in Rudin.

In order for a solid to precipitate from a solution:

Select one:
a. the solute-solvent forces must equal the solute-solute forces.
b. the polarity of the solute and solvent must be opposite.
c. the solute-solvent forces must be greater than the solute-solute forces.
d. the solute-solute forces must be greater than the solute-solvent forces.
e. none of the options

Its D, right? Don't believe I ever saw anything like this in the lectures or reading material

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Any ideas fellas?

>>8779372
what do you know about upper bounds and convergence?

>>8779384
Well, b will be an upper bound of A if for any x in A, b>=x. Also, if b_n converges then b_n has a LUB and GLB. I'm not 100% sure how to glue these ideas together though

>>8779398
have you been given any other definition of convergence?

Let's say someone who isn't me plants a camera and a pair of binoculars in a location and leaves it there for 24 hours. The sun is going to potentially shine on the binoculars and produce the famous reflection of the sun, that people in movies always see when there's a sniper with a sniper rifle.
My question is: how do i avoid the reflection?
Will it help if the binoculars are under a tree where there's no sunlight, or maybe if i put a towel on top of the binoculars.
>>8773374
>Are some languages harder to lip read?
Sure. You can produce sounds without ever moving your lips. You just have to find a language that depends mostly on weird "uh" and "eh" sounds, like French.
>>8773444
>Why isn't /sqt/ a sticky?
If it's a permanent sticky, the thread would end up growing too large and start lagging. It would also go against the idea of 4chan, where your posts are not supposed to be there permanently.
If you make it a temporary sticky, a mod would have to sticky it every day and that's effort. Just use the catalog to search for "sqt"

>>8779668
anti-reflective coating would help but your binoculars might have it already

the lens hood should be as tight as possible, maybe your binoculars already come with them built in but like if you're not using the full field of view you can make the hood even tighter

if you don't mind blurring the image a bit maybe you could experiment with putting stretched pantyhose or some specialty filter on the lenses like a curtain

>>8779723
>like a curtain
i don't mean an actual curtain but you know how you can peek through a thin curtain but the curtain still hides you from view

>>8779725
or like how robbers wear pantyhose on their heads to mask their identity but the robber can still see through it

Why are extensive properties additive?

>>8779723
>>8779725
>>8779732
Good idea, i'll try that.

Would reading mathematics-philosophy related books help with studying mathematics at an entry level? Or should I forget about them until I reach a more mature state

Ok, I've recently started learning science for fun, and doing my own little experiments, and after reading some termodinamics and how gasses work and stuff, I had a dream where I built a very weird looking machine, if it was a machine, some kind of aesthetically looking hollow cone made of wood
I didnt know how it worked, but I was sure what was its use
It was made to concentrate the sorrounding heat into a single point, the dot looking hollow part of the wooden structure
Dream logic aside, I decided to learn the basics for something like that to happen, and I found out refrigerators use something similar to this (apologizes for brainletting, I just very recently got into this)
I got way more interested in this, and will probably start building something similar to the dream I had, but I would need learning material, and dont know where/what to look for

Does someone got interesting books on everything heat/gas/cooling related? would love you to death

Also, the concept of heat/volume was completely introduced to me by that dream(a 10m3 room at 20 ºC doesnt have the same 'heat'/calorific energy as a 100m3 room at 20 ºC) and I didnt think anything about that before. Material sorrounding that is also apreciated

In context free grammars, is ε considered part of the language?
So if Σ = {ε, 1, 2, 3}, then the size of the language would be 4?

https://www.encyclopediaofmath.org/index.php/Geodesic_circle

References are unhelpful. Does anyone know of good sources on this? How do I find a parametric curve for a geodesic circle?

>>8780060
depends on the metric

>>8778252
It all comes down to this algebra transform:

if (a = b) then √a = √b OR √a = -√b

If you want to "take the square root of both sides of an equation", then you MUST apply the above transform fully, and you must investigate both branches, with the understanding that either or both branches might be true, and either or both might yield solutions.

However, the notational convention is that √a is defined to be ONLY the positive square root. If you want the negative square root instead, then simply use -√a. That convention makes sense, because it gives you total control over which of the two square roots you want to talk about. Despite this, you can still correctly say that "a has two different square roots" (provided that a > 0) -- notice I'm using the word "roots" instead of "root".

(If a is negative, then you must upgrade to the complex number system -- or, if you're not willing to do that, then you cannot apply the above transform and you must accept that sqrt(a) is undefined.)

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>>8779209
>This is a lie.

>>8780145
Let's say Riemannian.

Femanon here. Uni runs a couple of undergrad summer projects. Would it be ethical to suck the cock of one of the professors to get in?

>>8780323
>Would it be ethical to suck the cock of one of the professors to get in?

Did you think about this question before you typed it?

>>8780370
Yes? What do you mean?

>>8780323

unless your at least 9/10 good luck getting a prof risk his career

btw pm nudes

>>8779998
I don't think we ever looked at the size of a language in our formal languages class, because a lot of the time they're infinitely big.
But: the empty word doesn't have to be part of a language, so if it is, then it counts towards the size of the language, yes. It's not like o in sets.

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How do you go about solving this?

>>8780370
It's a false flag /r9k/ poster, dumbass.

>>8780455
quadratic formula brainlet

>>8780455

(x - a)(x - b) = x^2 -bx - ax +ab

now plug in any distinct number for a and b and find p.

>>8780323
of course it wouldn't be ethical. things like that might happen but it's not as common as /r9k/ wants to think it is and also >>8780445

>>8779998
No, the set of terminals Σ does not include the empty string.

The empty string only results from the application of some rule, where the right side of the rule is empty.

Here's a real-world analogy: There is no such thing as the "empty character", because each character is defined as the bit pattern of exactly 8 bits (assuming the ISO-8869-1 character set). However, you CAN have an empty string of characters, because a string is described by the regular expression C*, where C is one 8-bit character. Hence, a string can be of lengths 0 bits, 8 bits, 16 bits, 24 bits, etc. These different possible string lengths do not change the fact that each individual character is exactly 8 bits.

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How do I solve this limit without using the a^b=b*e^log(a) rule?

>>8779847
whatever you feel like, really
you could say that reading those books would make your studying harder or easier, it largely depends on you

>>8779976
>Dreaming a weird machine and trying to craft it with zero knowledge
You are a respectable brainlet. The only kind really, the one that wants/does learn stuff
Please post about your finished product

>>8779998
>So if Σ = {ε, 1, 2, 3}, then the size of the language would be 4?

This question uses poor terminology, which could cause some confusion.

The symbol Σ represents the set of terminals.

The set of terminals is not the same thing as the "language". The "language" is the set of strings that result from all possible applications of the rules. The "size of a language" may be finite, or it may be infinite. However, the set Σ is required to be finite in size.

I would change your statement to say it like this:

"If Σ = {1, 2, 3}, then the size of the set of terminals is 3."

I cannot determine the size of the language from your question, because you did not give me the list of the rules in your grammar.

>>8780473
multiply by 1 but in a clever way

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Is the function in pic related the same as:

f(x) = | x / 2 |

I have no idea what those lines mean if its not absolute value or cardinality.

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>>8780674
it means floor


https://en.wikipedia.org/wiki/Floor_and_ceiling_functions

>>8780674
it means floor, i.e. integer part

>>8780684
eh never mind, floor is not iteger part for negative numbers

>>8780684
>>8780679
thanks anons

>>8780660
(you)

>>8780700
hint for baby: m=1/(1/m) AND >>8780660

>>8773374
I need help /sci/. I can't seem to remember the name of a theory that basically states:

>Reality is dependent on observation. Therefore our universe must be absolutely perfect since we observe it. So perfect, that it makes intelligent design seem inevitable.

I know it exists, I wrote a paper discussing it. Does anyone know it?

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What phenomenon exactly makes light change its direction on the double slit experiment? I know it's not diffraction, because like in pic related, all light has the same intensity.

Light acts as a wave, and when overlapping from two sources, causes constructive and destructive interference.

The phenomena is diffraction. The relativity of the amplitudes of the wavelengths won't change that behavior.

>>8780804
Meant for >>8780772

>>8780804
But doesn't diffraction imply that the light slits appearing on the screen will decrease in intensity as they get further from the center?

I couldn't figure out why division by zero was undefined. All the answers I found were essentially "if it were allowed, all this other maths would be wrong", which frustrated me because it didn't justify why it was the division that was wrong instead of the other maths.

Finally, however, I came across this (paraphrased):
[math]\frac n 0 =\pm inf[/math] but neither inf nor -inf are in R or even C, so unless you are using an exotic number set, the output is not defined and therefore neither is the operation.

Now, that made a lot more sense to me- if an operation results in something outside the set of numbers within which you’re supposed to be working, it isn’t defined.

But, I’m now unsure how that squares with [math]i[/math].

[math]-1[/math] is in [math]R[/math] but [math]\sqrt{-1}[/math] is in [math]C[/math], so which of the following is correct?
>[math]\sqrt{-1}[/math] is only defined if you have decided from the outset that this problem is in [math]C[/math]
or
>An operation is allowed to break out of the current number set, i.e doing [math]\sqrt{-1}[/math] in [math]R[/math] is allowed to have a result in [math]C[/math]

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>>8780815
That has more to do with the nature of wave 'dissipation'. But yes, the further away from the center, the less intense it should become, due to photons being spread out over a greater area.

The render you have doesn't quite represent a realistic DSE.

>>8780830
>if it were allowed, all this other maths would be wrong

this is called proof by contradiction, in a formal proof you would specify which set you are working in first

you might find algebraic closure of rings/fields interesting

>>8780830
> I couldn't figure out why division by zero was undefined
Division is the inverse of multiplication.
x = y/z <=> x*z = y

y/z is only defined if there is exactly one x for which x*z=y.

If z is zero, then x*0=y. If y is zero, there are no solutions. If y is non-zero, there are infinitely many solutions. In neither case is y/z defined.

>>8780830
Say you have [math]\dfrac{n}{0}=x[/math].

The problem is that [math]x[/math] cannot be made to behave in a consistent way. Divergent series used to be undefined, but then they found out that any value assigned to a divergent series by a method, will be the same value assigned to it by every other method. So the important thing when defining undefined things is that they have to behave consistently.

This is also why infinity can't be used as a value; because infinity does not behave in a consistent way.

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help and undergraduate understand this

what i did

>we have 5t + 1 == 2 (mod 6)
>equivalently 5t + 1 - 2 = 6k
>5t - 1 = 6kt
>25t -5 = 6k'
>therefore 25t == 5 (mod 6)

i tried the following,

25 == 1 (mod 6) and t == 5 (mod 6) for some t, to get 25t == 5 (mod 6)

but is that the right to way to "easily" prove this? is not easy at all wtf mans

>tfw too brainlet to write 2-3 line proof

halp

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>>8780984
forgot to circle the question

>>8780984
>>equivalently 5t + 1 - 2 = 6k
>>5t - 1 = 6kt
where did the t after the 6k come from?

anyway for the right way to do this:
if 5t+1 =2 mod 6 then 5t=1 mod 6
now apply the inverse of 5 mod 6 to both sides of the modular equality and you're done

Is there a formal way to describe infinite nested roots and infinite nested fractions?

>>8781042
https://en.wikipedia.org/wiki/Continued_fraction#Infinite_continued_fractions_and_convergents
https://en.wikipedia.org/wiki/Nested_radical#Infinitely_nested_radicals

>>8781005

>where did the t after the 6k come from?

i fucked up that one. ignore that

>inverses modulo

i dont quite understand yet but....if 2 is the inverse of 3 modulo 7 say....then whenever 2 dot 3 on the left side it sort of cancel out??? for instance 2 is the inverse, then if i have 3t == 4 modulo 7

then (3)(2)(t) == 4(3) modulo 7 is equivalent to t == 12 modulo 7 because 3 and 2 cancels out to become identity or some shit.

>>8781078
>i dont quite understand yet but....if 2 is the inverse of 3 modulo 7 say....then whenever 2 dot 3 on the left side it sort of cancel out??? for instance 2 is the inverse, then if i have 3t == 4 modulo 7
>then (3)(2)(t) == 4(3) modulo 7 is equivalent to t == 12 modulo 7 because 3 and 2 cancels out to become identity or some shit.
almost
inverses (when they exist) satisfy
a*a^(-1) = 1 mod n

so if 5t=1 mod 6, then
5^(-1)*5t=5^(-1)*1 mod 6, which is the same as t=5^(-1) mod 6

and you compute 5^(-1)=5 mod 6 (since 5*5=25=1 mod 6), so t=5 mod 6

>>8781047
So the way of simplifying nested fractions/roots works for all of them, and that's why they don't need a special denomination like sums?

please tell me x = - 3

Solve the system of congruence x ≡ 3 (mod 6) and
x ≡ 4 (mod 7) using the method of back substitution.

before i literally kms, been sitting for 8 fucking hours doing this question, revising shit, WHY THE FUCK ODES EVERY BOOK SAY "ITS EASY TO SOLVE DIS" for all their fucking linear congruence practice REEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE

>>8781496
if you can't even verify your answer for a question that simple you've got some issues brainlet

go back to the start of the textbook and read, and do more exercises

>>8781498

x = -3 works, sure, but how the fuck do i know if its true? TFW A LITERAL BRAINLET FUCKKKKKKKKKKKK

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>>8773374
The loop to heapify the array works as intended but something is going wrong with the code to sort out the top value then reheapify the array, and I just can't figure out what I've got wrong. I can probably rewrite it so that the array reheaps from the bottom up again but I;d rather not brute-force it.

>>8780749
Anthropic principle.

A universe must inevitably have conscious and sapient life emerge within it for it to exist, due to existence being dependent on observation from conscious and sapient life.

In order for this to happen, all universal constants and laws must accommodate this inevitability. In a sense, every atom in the universe must be 'intelligently designed' to allow conscious observation.

So I'm a total pleb who just learned about how divergent sums can still be assigned values. The fibonacci sequence is a sum that is divergent if you take it on forever, can it be assigned a value?

>>8781566
Nevermind, I found it. The last fibonacci number is 1.

>>8779181
I was sweating bullets watching this

somebody explain Hox genes to me like I'm a idiot undergrad barely passing biology

Simple question guys

If I have -X^2 for example and X=2 , is it

(-X)(-X) = (-2)(-2) = 4

OR

-X^2 = -2^2= -4

>>8781715
Exponentiation takes precedence over the negative (much like exponentiation goes before subtraction in the PEMDAS method you're taught in elementary school)

So -x^2 = - (x*x). If you wanted to square -x you would write (-x)^2

>>8781528

go to /g/ my frieeeendedd

Can a closed form be assigned to a series that always diverges for values other than 0?

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How do you go about solving this?

>>8781889
quadratic formula retard

>>8781894
But it has multiple variables. I don't know how to solve it algebraically

>>8781889
It is a 3x3 system.

Let ax^2 + bx + c be our quadratic

So we have three equations with three unknowns.

a+b+c=0

25a+5b+c=0

b^2 - 4ac = 4

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"Show that there is an algorithm which receives as input a DFA M over the alphabet {0, 1}
and decides whether M recognises exactly the binary strings that contain an odd number of 1’s"

How do I go about doing this? Do I design a DFA and then detail the instructions on what to do for every step ?

>>8781909
Can you elaborate? I still don't get it

>>8781889
If the roots are 1 and 5, then the quadratic is
k*(x-1)*(x-5)
= k*(x^2-6*x+5)

The discriminant b^2-4*a*c
= (-6*k)^2 - 4*k*5*k
= 36*k^2 - 20k^2
= 16*k^2

So k is 1/2 or -1/2

IOW, the equations are
y=x^2/2-3*x+5/2
y=-x^2/2+3*x-5/2

>>8781940
Use the pumping lemma.

>>8781909
>a+b+c=0
>25a+5b+c=0
>b^2 - 4ac = 4
how do you find these? i don't mean how to solve them, but how to know that you want these specific equations

>>8782094
The problem explicitly states that the discriminant (b^2-4ac) is 4.
It also states that x=1 and x=5 are roots.
x=1 => ax^2+bx+c = a+b+c
x=5 => ax^2+bx+c = 25a+5b+c

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>>8773374
Are these any different?

>>8781940
For each state, identify whether it can be reached with:
1. An odd number of ones
2. An even number of ones

The initial state can be reached with an even number of ones.

If a state X can be reached with an even number of ones, and there is a transition X->Y for an input of zero, state Y can be reached with an even number of ones.

If a state X can be reached with an odd number of ones, and there is a transition X->Y for an input of zero, state Y can be reached with an odd number of ones.

If a state X can be reached with an even number of ones, and there is a transition X->Y for an input of one, state Y can be reached with an odd number of ones.

If a state X can be reached with an odd number of ones, and there is a transition X->Y for an input of one, state Y can be reached with an even number of ones.

If any state which can be reached with an even number of ones is accepting, the answer is "false".

If any state which can be reached with an odd number of ones is non-accepting, the answer is "false".

Otherwise, the answer is "true".

i feel like i'm wasting my time with proof(honors at my school) based math.

It's my first year, second term taking it, and it seems like i'm just memorizing these really complex proofs and regurgitating it on paper. I cant begin to comprehend how these people derived these proofs(ex. Bolzano–Weierstrass theorem) , whereas in 'computational math', it's quickly evident how the formula came into existence. Is this normal? or is honors math not for me? i'm too embarrassed to ask my instructor or class mates despite doing extremely well in the class

>>8782148
I am in second year and I feel this too. I really can not fathom how some of these derivations came about.

>>8781848
Okay, but my issue is a logic error more than anything technical so I thought /sci/ would be the better fit.

>>8782128
Read the book, there are formulae specifically for this.

>>8782171
the book? I am going through the course notes and there is no distinction noted.

>>8782128
No (assuming that there are at least 5 balls; otherwise you can't draw 5 balls without replacement).

In both cases, the expected value is 5 times the proportion of balls which are white.

>>8782185
Thought so but is there any good reasoning?

I've got a nerf gun that uses a rubber bladder pumped up with air to shoot the darts. The interesting thing about this mechanism is that it is self regulating, basically it takes a certain amount of pressure (in this nerf gun, around 25 psi) to start expanding the bladder, and once the bladder starts expanding it stays at that pressure. The bladder expands to about 4 times its size and maximum charge, and fires a shot of air about 1/8th that volume each trigger pull, giving you 8 shots.

My understanding is its not the air in the bladder that is providing the pressure but the elasticity of the rubber.

Could the same effect be achieved by putting an airtight piston with a spring on one end inside and airtight tube and pumping air in from the other end? would the air remain at whatever pressure is initially required to start compressing the spring with only the volume increasing as the spring is compressed and the piston moved further back in the tube?

>>8782187
The expected proportion of white balls remaining never changes. The probability distribution changes, but not its mean.

>>8782128
if you have 2 balls, 1 of which is white and 1 of which is black, if you draw 2 balls with replacement it's a 50% chance to get a white ball on each draw => 1 ball expected, if you draw 2 balls without replacement then 50% of the balls are white => 1 ball expected

>>8773374
when I'm playing loterry for example
what's the difference between
[math]49*48*47*46*45*44[/math]
and
[math]{{49}\choose{6}}[/math]
the first result is much higher
I pick one randomly
and again
and again...
why are the results different? what's the difference?
[spoiler]Yes I'm pretty dumb[/spoiler]

>>8782289
Factorial means the order of numbers matters. So 2 3 4 is not the same as 3 2 4

Binomic coefficient means the order doesnt. Ie 2 3 4 is the same like 4 3 2

So my uni is going to have few lectures from Cedric Villaini about a topic I have no knowledge about. I'm in my first year, too. Is it even worth it going there? It feels selfish to go there even if I won't be able to understand anything.

>>8782335
dude who gives a fuck if it is selfish. Don't miss that opportunity. Go to at least the first one and see how cool it is

>>8782289
> [math]49*48*47*46*45*44[/math]
This is 49!/(49-6)!
> [math]{{49}\choose{6}}[/math]
This is 49!/(49-6)!/6!. Which is smaller by a factor of 6! = 120.

Both give the number of "ways" of choosing 6 from 49. But the first one treats different orderings as different combinations, while the second doesn't.

The first counts "permutations" and is written as 49P6 or P(49,6); the second counts "combinations" and is written as 49C6 or C(49,6).

At what point does vibration become temperature?

Given two piecewise-defined functions [math]f(x)[/math] and [math]f\big(g(x)\big)[/math], how do I find [math]g(x)[/math]?

>>8782335
>It feels selfish to go there even if I won't be able to understand anything.
wut
Why would you feel selfish going to a lecture? You're not bothering anybody by sitting in and watching.

If it's a technical talk you're probably going to be somewhat bored out of your skull because it's just going to be an hour and a half of basically a foreign language, but if you're interested at all in math beyond undergrad it might be a good experience anyway to watch some "real" math events.

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How does one find the second answer ? Is it related to the unit circle?

>>8782695
yes

y=sin(theta) on the unit circle

and the circle has points on the left and to the right

so sin(x) = sin(pi - x)

>>8782723
Thanks. I don't understand the unit circle fully. I wasnt able to solve the second part even if i knew that it was related.

>>8773374
I'm working on a Project Euler problem and am having a bit of an issue:

It's problem 100 and it has to do with taking blue or red disks out of boxes such that P(Blue, Blue ) == 1/2

I got to the following Equations:(R = Red, B = Blue, N = Number of Disks)
N == R + B
B(B-1) = R(R-1) + 2RB, or
0 = R^2 -R + 2RB -B^2 + B

My question is, for a given N, how would I find B? The above two equations work for an N, B (or R, B) pair, but I need some way to find out these values... Any suggestions?

How do I into Calculus I ?
Scarred person transferring into a real STEM and calc 1-3 are requirements for graduation and I'll probably fuck up I don't know

I just want to not fuck these 3 classes up

What is the physiological reasoning behind my fetish for watching girls tinkle

>>8782763
Do a lot of practice problems, watch Khan Academy for something you're not sure, and just make sure you take it seriously. It's hard, yes, but it's not impossible to do well in.

>>8782765
>the President of the United States browses /sci/

Can you guys convert 2.2 x 10^4 mi ^2 to SI units please? And show each step as I'm trying to learn this stuff right now.

Can I assign a value to the last term of an infinite series?

>>8783411
>last term

Does anybody have that pic of the the fruits equalling a certain numer and the integral with the sin and cos on it> it has something like
>99.9% of people can't solve this problem

I've been looking for it, but completely forgot which thread it was in

What does (n, 1/2) mean? It's supposed to be a binomial number. I'm not a mathematician, clearly.

>>8783632
context?

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>>8783635

do you sometime wish you had more intelligent friends so you friend wouldn't always compare themself to you and be basicly the cause of their failure

>>8783655
binomial distribution, not binomial number

https://en.wikipedia.org/wiki/Binomial_distribution

(p=1/2)

Anyone have that "CS Core" infographic?

>>8782148

Well, if you memorize it long enough you might understand it at some point. If you get the gist of it its fine IMO.

>>8782156

a good mentality when dealing with higher math is that remember, some people devoted their LIFE to this, and you are learning about in 2~3 months, dont feel bad about it. Every mathematician is sitting on the shoulder giants, whom are sitting on the shoulder of other giants.

Do you guys know of any resources on the internet that have 3D representations of the human skeleton? Like, basically an online Atlas of Human Anatomy?

Someone share some resources on program correctness?

Prove algebraically that the difference between the cubes of two consecutive odd numbers, less two, will always be a multiple of 24

>>8784286
what have you tried... there's literally only one thing you can do to do this and you get the answer in like 2 lines

>>8773374
http://drinkh2o2.com
>Bathing in 3% hydrogen peroxide. Do not try this before bedtime, because the absorbed oxygen energizes the body and prevents sleep.
So called "scientists", why has the government and big pharma kept the truth about healing powers of hydrogen peroxide from the people?

>>8784316
x^3-(x+2)^3-2 mod 24 = 0
thats about as far as i got

>>8784335
you didnt use the part about x being odd

and you dont know its equivalent to 0 mod 24 yet, you're not suppose to start with what you're trying to prove

>>8784341
you're right, i just don't know how to do it otherwise

>>8784351
you have an (x+2)^3 in there.. you might as well expand it

>>8784354
6x^2+12x+6

i'm just confused about what the question is asking me to do

>>8784324
You don't seem to understand how easy it is to get oxygen poisoning. Breath really fast for 10 seconds. Imagine that feeling, except you can't make it go away and you're also submerged in a tub of liquid.

>>8784387
do you not know what odd numbers look like?

rewrite x as an odd number instead of just an arbitrary number

once you do this you'll get something with a 24 in front

If the cross product is associative, then how is [math]X \times Y \times Y[/math] not zero? If you do it left to right, you will get the vector X again.

>>8784401
>If the cross product is associative, then how is X×Y×Y not zero?
because its not associative brainlet

>>8784404
[math]A \times B = -B \times A[/math], retard.

>>8784404
Not him, but are you sure you aren't the brainlet here?
http://mathworld.wolfram.com/WedgeProduct.html

>>8784413
that's anti-commutativity brainlet, not associativity

try again

>>8784418
that's the wedge product brainlet, not the cross product

try again

>>8784392
so i just have to give an example?

>>8784423
no, it's for all odd numbers...

even numbers look like 2k for some integer k, so odd numbers look like...?

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>>8784421
Wedge product and cross product are literally the same thing on R3
Or are you just pretending to be retarded?

>>8784429
https://en.wikipedia.org/wiki/Cross_product
>The space R3 together with the cross product is an algebra over the real numbers, which is neither commutative nor associative
>nor associative

are you brainlets really going to pretend the cross product is associative when the person who originally asked literally gave an example showing it's not associative? (XxY)xY = ZxY=-X while Xx(YxY)=Xx0=0

>Wedge product and cross product are literally the same thing on R3
wrong again brainlet, the cross product is the hodge dual of the wedge product:
https://en.wikipedia.org/wiki/Cross_product#Cross_product_as_an_exterior_product

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>>8784441
>wikipedia

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>>8784452
>citing the wedge product on mathworld.wolfram to say the cross product is associative when it's obviously not

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>>8784456
>wikipedia is more reliable than math world

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>>8784460
sure seems that way

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>>8784464
enjoy not having $300k starting

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>>8784466
i already have my math degree

try again

>>8784487
>math degree
no, I don't want any fries

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Why is [math]u_{\nu}=2 \pi \rho[/math] if they are both spectral energy density? What am I missing?

>>8779398
really? no epsilon delta stuff?

a squence converges to b if there exist an N such that for all n greater than N |bn - b| < epsilon for all epsilon grater than zero.

I'd imagine you would do a proof by contradiction.

>>8784401
>the cross product is associative
wrong

>>8784452
>having to rely on a source for an obvious fact which you can figure out on your own if you're not a brainlet

ayy boye,

find the sum of

1/2 + 1/6 + ... + 1/(n^2 + n)

testing for n = 1, 2, 3 shows that its n / (n + 1)

but i dont know how to necessarily prove it. I guess I can use induction but can i prove it any other way?

i want to get better at math so i can understand physics and chemistry. is khan academy a valid way of doing this

also is duolingo a meme or can i learn a language from it