/sqt/ - Stupid Question Thread

Why is Nozomi so fucking UGLY

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explain this

motion is an illusion only we can see. it has to do with how our brain can divide and count experiences in the present. a rock for example understands all and all understands it theres no motion it's just everything everywhere all the time.

this whole universe and our whole existence is just a flash. like a nanosecond of light, like God snapped his fingers and there was a tiny spark and then it was no more.

I was accepted to a Masters program for next semester, but I want to switch to PhD as soon as possible. I figured I would start emailing professors now to get into a lab, but are there any other tips for increasing my chances?

/adv/ is retarded for this kind of question, so no redirect pls.

Anyone here know much about state space modelling?

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I know the answer is 14 but how does one arrive at that conclusion without a calculator/computer/trial&error?

What is some good software for learning mathematics?

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I can't do this and luckily the example question doesn't have an example answer, thanks a lot Prof

>>8705971
It has to be greater than 10 as 10^10 has 10 digits
Then AFAIK it's trial and error for 11 12 13 and 14

>>8706017
literally trivial, just write out what [A,BC] and [AB,C] are and you'll see the others pop out

put some effort in brainlet

>>8706008
What do you mean? The best way to learn mathematics is to be taught it by a good teacher. Second to that is a good book.

Software like matlab and mathematica are tools we use to help arrive at a solution.

>>8706023
I've tried that and it's not obvious to someone who's just learnt this how ABC - BCA is related to [A,B], [A,C], [B,C]

>>8706032
https://en.wikipedia.org/wiki/Commutator#Identities_.28ring_theory.29

ABC-BCA=ABC-BAC+BAC-BCA=[A,B]C+B[A,C]

>>8706046
Cheers, I nearly got that but got a sign wrong on one of the BACs so they didn't cancel

I am confused because I can't apply Lagranges Theorem to this problem [math] $ \langle 2 \rangle / \langle 8 \rangle \text{ where } \langle 8 \rangle \subseteq \langle 2 \rangle \subseteq \mathbb{Z} $ [/math] since G infinite. How should I approach this problem?

>>8706962
I forgot to state the problem :), the problem is to find the order of said quotient group.

>>8706966
>>8706962
<2> = multiples of 2
<8> = multiples of 8

so <2>/<8> = multiples of 2 mod 8 = {0,2,4,6} which has order 4

Can somebody tell me why Oct4 is relevant for the animal pole during embryo development?

>Cindy: zika virus is killing everyone!!
>Travis: nah b that's just what the media/facebook wants you to believe

>Cindy: bees are endangered!!
>Travis: yeah true we all fucked

So is the bee thing another phony fact or is it true? I tried googling it but couldn't find a definitive answer.

>>8707056
Bees are dying off to some degree, and the consequences of their extinction would be dire. How much their situation is really at the edge of a cliff is less clear. But it's not the kind of thing where you can afford to be careless and hope for the best so assuming the worst is the wiser option.

>>8705718

Mostly because for every force in the universe to be so exactly balanced as to cause no relative motion, every particle would need to be placed in an extremely ordered and uniform arrangement that would never come about naturally.

Small variations in density of the early universe led to clumps of matter forming massive 'webs' of galaxies given time for the gravity of the gas clouds to collapse themselves. The energy of the collapse plus the energy released by fusion of atoms in stars is what produced the potential for more complex small-scale motion that we observe.

Also quantum effects allow and indeed force very small particles to move, no thing can exist at absolute zero.

>>8707056

Zika virus behaving like the common cold is probably one of the spoopiest health crisis scenarios I can come up with, it'd be like Children of Men but instead of no babies there'd be a huge number of literal brainlet babies that we would have to deal with one way or another.

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Is citing a textbook exercise to reference a mathematical fact considered to be in bad taste?

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helb bis drainbet

>>8707381
First note that [math]a \equiv b \mod m \Longleftrightarrow a - b = km[/math] and [math]c \equiv d \mod m \Longleftrightarrow c - d = lm[/math] for [math]a,b,c,d,k,l,m \in \mathbb{N}[/math].
Then: [math]a + c = b + d + m(l+k) \Longleftrightarrow a+c \equiv b+d \mod m[/math].
Also: [math]ac = bd + m(dk + bi +m) \Longleftrightarrow ac \equiv bd \mod m[/math].

Anyone know of a good computer mathematics course available online? I bombed the final exam last year, and I'm hoping to catch up over the summer after retaking the intro course this semester.

>>8707438

yea i just got confused, i thought a triple equal b mod m is b = mk + a

sry for retardation

so i just had a midterm and one of the question was:

>if p and q are prime, then p + q is composite

so all i did was take p = 2 and q = 3, then we have p + q = 5 which is not composite

its a 6 marks question so im spooked a little now if im just not seeing something horribly obvious.

How do I know if a STEM field is right for me? What do I do when I find out it isn't?

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I am very well aware that the equation of a line is: y - y1 = m (x - x1)

So if I wanted to build a f(t) based on pic related what I would need to do is get all the slopes, calculate the average then sum all X´s and Y´s, get their average too, and then that would be my function right?

Am I processing this correctly or am I just extremely dense?

When is L(A) considered regular and when is L(A) considered context-free?

I would've thought if L(A) is regular, it's automatically context-free because any regular language can be expressed using a CFG.

What's the difference in angular momentum equations for hoops and discs?

>>8705718
How do i do this ?
>http://math.stackexchange.com/questions/118832/how-are-3d-coordinates-transformed-to-2d-coordinates-that-can-be-displayed-on-th

I have a very basic math level and i don't understand most of the formulas here. Could anyone explain this process with easy words ?
Thanks

Anyone else feel like a master's is actually easier than a bachelor's? In my bachelor's studies, i had to fight through so many classes that were seemingly just there to "weed out" students, but now i feel like i can study what i really want and what i'm really interested in. the stuff is arguably more advanced and more complicated, but i don't mind because i'm genuinely interested in all of it

Are quantum computers basically what analog computers would be if not for the noise?

>>8707661
Well yeah if you're motivated it all comes easier. Good for you anon

>>8707661
>Anyone else feel like a master's is actually easier than a bachelor's?
Everything is easier when you're 22-24.

>>8707225
no it's alright. if you follow the citation rules, you can cite almost everything.

>>8707609
You take a 3d objet and send it full force on a wall so that nothing bounces and stay exactly where it hit the wall.
In other words, you make a coordinate change so that your wall is a linear space, and then you project everything on it using a linear projector. Or maybe you can just use affine projector.

>>8707755
I've heard a story once that in some big math competition one of the contestants in order to save time wrote something like "the solution to this problem can be found in book X under section Y", and the committee qualified that answer, but changed the rules so that if the contestants wanted to do something like that again in the future, they would have to write the exact page number.

>>8707496

senpai plz answer me

If I have something like sin(5x^2) is there a way to quickly calculate the value without a unit circle or calculator?

>>8707496
>>8707847
Well surely p and q must not be 2

>>8707875

but 2 is a prime right? whats so wrong with that?

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I am preparing for a test.
Pleas explain this to me.
I am at a loss.

>>8707577
There are many different interpolation algorithms.

If you wanted a single, linear function, you'd typically use a least-squares fit.

For a piecewise-linear function, you'd take the two points on either side of the independent variable and interpolate the line through the two points.

Higher-order functions (e.g. splines) use more points .

>>8707578
> I would've thought if L(A) is regular, it's automatically context-free
That's correct. Regular languages are a subset of context-free languages which are a subset of context-free languages which are a subset of all languages. Chomsky hierarchy.

>>8707889
if you are allowed 2, then the test setter made a booboo

>>8707445
khanacademy can be helpful for learning but it isn't really a full-fledged course

>>8708020
KhanAcademy is indeed very useful, but it aint gonna give me my math credit.

>>8707862
>without a unit circle
you don't need to keep any special hardware around for that shit anon, you just remember some key values
if it isn't some easy key value and you don't have a calculator then you aren't gonna get a very exact answer though. before calculators people just looked these up in bigass tables printed on paper, so it's not like there's an easy way to calculate it by hand.
'course if all you want is a rough estimation you can just draw out a circle and try eyeballing it

>>8708025
you'll need to ask their school who they accept credits from then, since not all schools will accept all online classes.
in fact the school probably has some suggestions for online summer-school classes, if you ask them

>>8708038
I am, I am. They've got a two-day waiting list on replies though.

>>8707496
>>8707875
if it really said "+" and not "*" then it's trivially false, probably just a trick question and you answered right

>>8708035
I got that on a calculus 1 test (limits). We weren't allowed to use any calculators nor did we have the tables. As you say I guess I'll try to eyeball next time then...

>>8708015

alright, nice.

>>8708076
Did the test actually want a numerical answer?
In a non-calculator test they'd usually be perfectly happy with a response like "the answer is sin(45)"

>>8707974

>posting horizontally

i hope u fail dude i dont wanna break my neck.

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I'm trying to figure out what is meant here when talking about alphabets. Is this a concatenation of an alphabet?

If it is, how do I define a concatenation of an alphabet? all possible strings of length 2? or is it just sigma*?
The alphabet is {a,b}

>>8708178
[math]\Sigma = \{a; b\}[/math]
[math] \Sigma^2 = \Sigma\Sigma = \{aa; ab; ba; bb\}[/math]

>>8705718
Why is Nozomi so fat?

>>8708191
Thanks.

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how long, what is your experience ? dindunuffin

What degree should I go for if I want to build help build mechas like out of my japanese cartoons?
I'm 19 and applying for university this year probably to do maths because I don't know what I should pick, I feel like I should be doing engineering but not sure what kind, please help

>>8708116
Well I kinda gave an example from the top of my head, sorry. The actual task was:
Find the limit of (x^2tan(5x^2))/(sin(2x))^3 as x approaches 0.

>>8708350
Business studies, finance, law. Something that will help make you a millionaire. Because no-one else is going to pay you to make expensive-but-useless toys.

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Why does mass exhibit the property of inertia?

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>>8705718
ok, this really qualifies as a stupid question

can someone native in english help me to google this
>calculate the surface temperature at different layers within a cavity wall
so it actually provides useful links?

its mental that this is supposedly the easiest task of my course work, but its still driving me crazy

>>8708377
Serious answers only pls

>>8708371
Well that should be easily solvable without a calculator then. Sines cosines and tangents are all 0 or 1 around that area. You just needed a little help from your buddy L'hopital.

>>8708394
I mean...it should be just a simple application of fourier's law, no? Find your heat in/out and be carful with your control volumes/surfaces

>>8708371
> Find the limit of (x^2tan(5x^2))/(sin(2x))^3 as x approaches 0.
It's zero. And the slope is 5/8. Small-angle approximation.

As x->0:
sin(2x)->2x
tan(5x^2)->5x^2
(x^2*tan(5x^2))/(sin(2x))^3 -> 5x^4/8x^3 = 5x/8 -> 0

>>8708430
yeah, im fairly sure im doing something wrong, but I seriously cant say what

also I dont know how in gods name I should use fouriers law to calculate the surface temperature (read: the difference between the room temp and the wall surface temp [facing the room])

its funny because the rest of the course work (which should be way harder, was very easy for me lol)

>>8708441
Post more problem details and I'll see if I can help explain it in a reasonable way?

>>8708452
give me a sec, I'll draw something in paint

>>8708433
Fuck, that's actually so easy then. Thanks a lot, anon.

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>>8708453
>>8708452
>>8708441
alpha is the heat transfer coefficient (i for inside, o for outside)

1,5 is 1.5 (forgot that you guys handle that differently)

>>8708500
oh and this is how I tried to do it:
for the surface temp (inside)

t2 = 20 - (500*0,015)/(0,76*50) = 19,8°C

which is wrong, it should be 18,9°C

>>8708500
Where is that 500 W coming in/out?

Why does /sci/ substitute the word senpai for senpai?

>>8708526
Im not sure I understand your question but its the heat loss from inside to outside

calculated like this
q = k * delta T
q = 0,25 * (20-(-12))
q = 8 W/m^2
Q = 8 W/m^2 * 50 m^2 = oh fuck that no 500

well, it should 400 W, but even if, it doesnt change too much

20 - 40*0,015/0,76*50 = 19,8421

:/

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>>8708555
Might be off, but i think you can get the idea. you use your known heat flux to find your surface temp and work inward from there.

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>>8708650
Diagram wasn't copied for some reason

Doing an induction proof and fucking up the algebra.


When you have

(k^2+k)/2 + (2k+2)/2 why does this equal (k^2+3k+1)/2 vs (k^2+3k+2)/2

what is bernoulli's eqn useful for?
I have an exam tomorrow and I am going to fucking fail at this rate. Being addicted to this hellhole doesn't really help either

>>8708724
>(k^2+3k+2)/2
it equals this one because k^2+k+2k+2=k^2+3k+2

>>8708738
basically tells you how pressure and energy relate into each other, if you increase this then that decreases and blah blah blah, do some problems

>>8708754
alright, thanks

>>8708758
dont forget kPa is the SI unit for pressure and there is about 101.325 kPa in one atm

>>8708762
My book (Principles of Physics, Wiley) says its Pa though

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>>8708752
weird, my book has this

>>8708780
its just a typo, especially since (k+1)(k+2)=k^2+3k+2

>>8708782
ok good, thanks i thought i was being retarded and having a crisis.

>>8705718
Take any 10 sequential positive whole numbers. Divide it in two non-empty sets A and B. Can there be such number sequence and such division that least common multiplier lcm(A) + lcm(B) = 2016?

I'm assuming there can't (I just think the exercise is not to just crunch numbers). I tried to look at parity, and some basic divisibility, got nowhere. The only maybe-useful thing I came up with is realisation that always at least one of the sets has lcm divisible by 10.

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Any good book about determination of heavy metals in water?

Bonus point if there is a torrent of it

>>8708785
Progress update: the sums of lcms, seems if it ends in digits "016", the fourth least significant digit (a in "a016") will be odd. This is just a computed result (yay for Sage), that holds pretty high. Not sure why, any ideas?

>>8708656
>>8708650
fuck forgot about my question on here

thanks buddy, I'll report back if it worked :3

>>8707982

I get ya.

But is what I was doing correct in any way?

>>8708785
Notice that [math]2016 = 32 \times 9 \times 7[/math].
Consider 10 consecutive numbers [math]k, k+1, \dots, k+9[/math]. Assume that there is a partition (A,B) such that lcm(A) + lcm(B) = 2016.
Among your 10 consecutive numbers, one of them is divisible by 9, hence at least one of lcm(A) and lcm(B) is divisible by 9. But 2016 is also divisible by 9, hence both lcm(A) and lcm(B) are divisible by 9.
Consequently, your sequence contains two multiples of 9 (consider the 3-valuation of lcm(A) and lcm(B)). The only way this can happen is if k is a multiple of 9.
By the same argument, lcm(A) and lcm(B) are both divisible by 7, hence the sequence contains two multiples of 7. This can only happen if k, k+1 or k+2 is a multiple of 7.
Hence, k is a multiple of 9 such that either k, k+1 or k+2 is a multiple of 7. The least value of k such that this happens is k = 27. Hence [math]k \ge 27[/math].
Finally, the multiples of 7 in the sequence are among k,k+1,k+2,k+7,k+8,k+9 and the multiples of 3 in the sequence are k,k+3,k+6,k+9. Hence, k+4, k+5 and 63 are pairwise coprime.
If k+4 and k+5 lie in the same half of the partition, say A, then since 63|lcm(A), we have 63*(k+4)*(k+5) | lcm(A), hence lcm(A) > 63*(k+5) >= 2016.
If they lie in different halves, say k+4 in A and k+5 in B, then 63*(k+4) | lcm(A) and 63*(k+5) | lcm(B), hence lcm(A) + lcm(B) > 63*(k+5) >= 2016.
In any case, we see that we can't get exactly 2016.

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Let a=((250*251)/2)

Where does the 2 in 2*(a) come from?

I understand a, as that is the closed form of some from 1 to n. I don't get the 2 part being multipled by that though?

>>8709123
... its the 2 that got divided out from all the even numbers from 2 to 500

>>8709139
Ok that makes sense. Thanks.

>>8707609
See this. http://machinethink.net/blog/3d-rendering-without-shaders/

>>8708804
http://www.inc.bme.hu/en/subjects/inchem/sillabus/129-145.pdf

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>>8708542
that's a global filter, it's on all boards

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Pic related. Anyone has any example for these sequences?

Source: Abbott's Understanding Analysis

I do not understand it yet.

And I mean with the extra challenge. Without the challenge then take any divergent sequence and then add a bunch of 0s inbetween so that then the minimum just ends up being 0+0+0+0+0+0...

>>8709258
maybe something like
a_n= 1/n for n odd and 1/n^2 for n even
b_n= 1/n for n even and 1/n^2 for n odd

>>8709279
Shit you are a genius.

>>8709315
Why is [math] \Gamma{(x)} \Gamma{(1 - x)} = \frac{\pi}{\sin(\pi z)} [/math]

>>8709450
>Why is [math] \Gamma{(x)} \Gamma{(1 - x)} = \frac{\pi}{\sin(\pi z)} [/math]
Euler's reflection formula

>>8709279
1, 1/4, 1/3, 1/16... is not a decreasing sequence

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How many rocks would it take to blow up all of russia?

>>8709945
1 really big one

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How many hours should someone spend studying in one week as a minimum (in a week) to be a top student?

What is /sci/ opinion on Quantum Cryptography?

>>8710112
My college says you need to do at least half of the time you spend in college lessons studying at home (we have 4.5 hrs of class per week for every subject you take; I take 4 classes, so in my case I do 9 hrs of studying per week)
I've been sticking to this formula since November and my grades have gone up from low Bs in october exams to mid As across the board now

>>8709900
Yes I know what it's called. But that doesn't explain WHY

>>8710414
https://proofwiki.org/wiki/Euler%27s_Reflection_Formula

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I need answers on what is this ''gum'' on some water plants i found,i really wanna know what the fuck is this thing that melts when you touch it

In radiocarbon dating, how do scientists know how much carbon the sample contained originally? Do they just make an estimate and calculate the age based on that or how is it done?

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I have a math question:

Why is the average value of a function
[math]
\frac{1}{b-a}\int_{a}^{b} f(x)dx
[/math]
sometimes numerically different than simply averaging the function at points a and b (and dividing by the range)
[math]
\frac{f(b)-f(a)}{b-a}
[/math]

Is light particles or waves?

>>8710424
fish or amphibian eggs

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what should I do my nuclear engineering presentation on this semester?

Last semester I did Chernobyl. I know my professor dislikes thoriumfags

>>8710962
[math] f(b) - f(a) [/math]
equals
[math] \int_a^b f'(x)\, dx [/math]
and can be completely different than
[math] \int_a^b f(x)\, dx [/math]

Consider, for example, the case where [math] f(x)=7 [/math] for all [math] x[/math] . Then [math] f(b)-f(a)=0 [/math] while [math] \int_a^b f(x)\, dx = 7 (b-a) [/math]

Integrals over the domain provide averages.
Why do you think of [math] f(b) - f(a) [/math]? An average value estimate would be [math] (f(b) + f(a))/2 [/math], but one which doesn't incoorporate all values x, like the integral does.

>>8710972
Both
Particle of light exists as a photon
Wave; see double slit

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>>8711032
Thanks for the explanation!

I think I mis-typed that.. I meant to say f(b)-f(a)/2

>>8710414
You can also few it as an immediate corollary of

[math] \zeta(s) = 2^s\pi^{s-1}\ \sin\left(\frac{\pi s}{2}\right)\ \Gamma(1-s)\ \zeta(1-s) [/math]

https://en.wikipedia.org/wiki/Riemann_zeta_function#The_functional_equation

which is first proven in Riemanns original paper (my favorite paper), which you can find here

http://www.claymath.org/sites/default/files/ezeta.pdf

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I'm not sure how to do the question in pic related, the problem is supposed to use P(A&B) = P(A|B) * P(B)

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Why does hair stand up when you touch those balls(also whats the name of those balls)?

>>8711090
Tesla coils, and it stands up because the charge on the metal ball distributes itself across the hair strands, and the similar charges between hair strands repel each-other.

>>8711105
thanks, friendo

>>8711090
The overall device may be a Tesla coil or it may be a Van de Graaff generator.

There's no particular name for the spherical part. Potential field strength is highest at sharp corners, so a sphere minimises this and prevents the charge from leaking away.

When dividing polynomials, how do I know what the power of the quotient and the remainder will be?

>>8711291

The remainder will either
1) have a degree that is necessarily lower than the degree of the divisor
2) be 0 (which has an undefined degree)

f(x) = d(x)q(x) + r(x)
remainder has degree lower than d(x) so it doesn't change the degree.
so, deg d*q = deg f
so deg d + deg q = deg f

and ggwp

>>8710962
Why is the average of a list of numbers not always the average of the first and last numbers?

>>8710957
Anyone know?

>>8710957
c14 is constantly created in the atmosphere and as such there is a background amount that, whilst a living thing is alive and exchanges with carbon with the environment, is maintained within a living thing. when the organism dies, it ceases that transfer, and the levels of carbon 14 begin to lower as time progresses
tldr there is a "base rate" of c-14 that most living things start at.

>>8711457
How do they know the initial mass for a specific organism then? Wouldn't it be needed to know the amount of carbon there was at the beginning? Do they just kind of guess or what?

>>8707609

The way it works is coordinates are transformed by a projection matrix.

If you just want to do 3d graphics, you wouldn't reasonably do this. Use a library like GLM to get a projection matrix and then you'll have to tweak it's settings

>>8710112
it's not about how much time you spend studying it's about how clearly you understand the material
if you study for a billion hours but still have trouble understanding the subject, you aren't gonna magically ace your next test
study until you are confident in your understanding of the material
if you aren't making progress on your understanding, you need to either change your methods or go seek outside help

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working on this ray tracer. right now the reflection calculation is broken.

this is what it looks like when the normal is used as the reflection. What it should do is use the normal and incoming ray to reflect the incoming ray across the normal

Now I'm trying to debug this algorithm I thought up. It doesn't work in code and I don't know if it should even work in theory

> get the vector that is perpendicular to the normal and "under" the incoming ray
> get the dot product onto the "under ray" and the normal of the incoming ray
> now it has the incoming ray written as the sum of two vectors
> multiply the "under" vector by -1
> add them up to create the reflect ray

Should this work?

>>8711483
Things have a mix of C14 and C12. Only the C14 decays.

If 1 in 100 carbon atoms were C14 (actually the number is way different and much smaller) then if you had an organism with 99 grams of Carbon-12 you know that it USED TO have 1 grab of carbon-14, before decay set in.

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Im a bit confused by the notation in pic rel. Where is the point about which the moment 40Nm is acting?

>>8711631
It doesnt matter where, just the axis and direction.

>>8711654
so 40nm is a torque on the entire system?

If disturbing the entangled twin of a quantum particle in a double slit set up causes the pattern to change, how is this not sending information through quantum entanglement? You can tell if somebody is screwing with the other particle stream this way, can't you?

>>8711655
Yes.

>>8711831
Thanks
when finding the conditions of equilibrium, once i've accounted for that on one axis, do I also have to account for it on the other axis? (for instance, if a 600N force is applied downwards at A that makes the moments about roller B even). If I want to then find the moments around the bottom of the overhang on the right, do I no longer account for the 40Nm (given that it is already 'countered' by the 600N applied at point A?)

>>8711864
It doesn't just disappear anon. It'll go in all your moment equations.

Can someone tell me if learning how to write assembly code is useful as an EE major

>>8711879
okay, thanks man you've helped me out a lot

>>8711883
yeah definitely

>>8711922
Any specific processor family? Or are they all essentially the same

R=Z_r-5+0j

How do you find R?

what if the universe is shaped like a cok? is God taking it up the ass?

>>8712001
it's before the equals sign.
your welcum

>>8711992
couldn't tell you as im not in EE myself but i have a friend who studies it that bitches about how much assembly they have to write

I know this is /guaranteed replies/-tier bait but I'd really not make a bait thread. It makes me really skeptical of science as a replacement for believing in a Creator when we really don't know all the answers.

If the Big Bang created the universe out of nothing, who created the Big Bang? Something cannot come from nothing. Feel free to call me a faggot, or understand and be nice enough to realize I'm really trying to understand how people can believe this.

>>8712036
>who created the Big Bang?
a tenth dimensional being of course.
either that or membranes smashing into each other like windshimes

>>8712035
I see, thanks

>>8712044
>a tenth dimensional being of course.
>either that or membranes smashing into each other like windshimes
well shit, I cannot argue with dubs

>>8705718
>first year into Mathematics major
>work is easy
>cruising
>killing it
>integration is fun and easy
>run into pic related
>factorising is my achillies ballsack

Helb me pls, it's an even exercise question and it only pops up once, I just wanna see someone do it quick so I know I'm on the right track.

>>8712073
check out this long ass video
https://www.youtube.com/watch?v=gg85IH3vghA

it has annotations so you can jump to info on each dimension. string theory is some cool ass shit anon.

>>8712094
nice pic

>>8708350
All kinds of it. EE MechE 'Energy'Engineer.

>>8712099
ok I'll watch. thanks

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>>8712094
Fug, this is why I shouldn't stay up so late.
I think I got her though, never had to do polynomial long division without facorisation before. Even though it appears to be a fairly basic concept online.

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>>8712136
>factorisation

>>8712138
It's been nearly 3 years since I did this.
I know it's pretty ebin that I didn't know how to solve this, but I got it now, right after posting the question.

Now onto two term polynomial division...

>>8709258
a(n) = 1/2^n odd , (2^(n)-1)/2^(n+1) even
b(n) = 1/2^n even , (2^(n)-1)/2^(n+1) odd

a(n) + a(n+1) = 1/2
min(a(n),b(n)) = 1/2^(n) odd , 1/2^(n) even
a(n+1)<a(n)

If f(x) = (ax^2)/(bx), how does dividing the function by x imply f(x) = a/b, and not f(x) = (ax)/b?
For instance, g(x) = [5(9)]/[4(3)] = 1.25; and 5/4 = 1.25.

>>8712250
For clarification, the numerator and denominator are each being divided by the nth degree of x present in the numerator and denominator respectively, and not by the nth degree of x in the denominator alone.
The problem is:
lim as x -> infinity f(x) = [(sqrt(7x^2 + 1))/9x - 7]. Simplifies to (sqrt(7))9.

>>8712036
>who created the Big Bang
well the Catholics say God did
science and religion in general aren't at odds
it's just science vs retarded american evangelical christianity

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What the fuck is the order of transforming an elementary function? Why the fuck is it the minus coefficient first, then additive +3 inside, then additive +1 outside AND THEN the numeric coefficient 2? WTF?! Why the fuck does it even matter? The fuck?

Please explain this moronic bullshit somebody shit out of their asshole on a chilly day.

>>8712255
because the one in the numerator isn't x^2 it's sqrt(x^2)

>>8711618
So if we measure the total amount of carbon an organic sample contains and then measure how much carbon-14 it has left, we can calculate how much carbon-14 it must have had initially since the ratio of carbon-12 and 14 is known? I mean, if we measure the total amount of carbon and after that measure the amount of carbon-14, we can know how much carbon-12 it has by subtracting the amount of C14 from the total amount of C. And after that we can calculate the initial amount of C14 with the ratio we know.

This whole thing is making me feel stupid but I'm really just trying to understand how the process works.

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>How much ammonia does can a fish produce on average?
Im trying to find a way to predict or at least form a rough estimate on how much ammonia a fish of certain variables could produce. Everytime I ask /an/, other forums, or google it all I get is regurgitated information of how to cycle a tank so that it is converted into nitrites/nitrates, which is not really what Im asking. I need the ammonia concentration for figures relating to non-aquarium purposes.
My spectrometer is only capable of testing metals, and with the contaminates and ongoing bacterial processes in samples testing ammonia concentrations by pH or titration hasn't been very successful.
I know it can vary based upon size and biology of the fish's digestive system, temperature, amount of amino acids/proteins in the food, ect. But is there a formula somewhere out there that I have missed that can give me a basic estimate of concentration/volume of water/time?

>>8712382
Everyone loves a square. Weird thing about most maths.

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What the fuck is the order of transforming an elementary function? Why the fuck is it the minus coefficient first, then additive +3 inside, then additive +1 outside AND THEN the numeric coefficient 2? WTF?! Why the fuck does it even matter? The fuck?

Please explain this moronic bullshit somebody shit out of their asshole on a chilly day.

More of an economic question, but I think someone here will be able to help.

If a person (let's assume a US citizen) were to stop working for the rest of their lives, how much would it cost the economy? An average US citizen makes about $1.4 million in their lifetimes, so I imagine that's a good starting point.

I am suppose to show that [math] \mathbb{Q} / \mathbb{Z} [/math] have elements whose elements are of finite order.

One element of [math] \mathbb{Q} / \mathbb{Z} [/math] is [math] S = \{...,-2+\frac{a}{b},-1+\frac{a}{b},\frac{a}{b},1+\frac{a}{b},2+\frac{a}{b}, ... \} \in \mathbb{Q} / \mathbb{Z} [/math]

Suppose [math] a=3, b=4 [/math], then one element in [math] S [/math] is [math] \frac{3}{4} [/math]

By definition of order, the order of any element [math] a [/math] is the smallest positive integer [math] n [/math] s.t [math] a*n = e [/math] if group is additive.

Therefore the order of [math] \frac{3}{4} [/math] is the smallest positive integer [math] n [/math] s.t [math] n*\frac{3}{4} = 0 [/math] which is clearly never the case so the order of [math] \frac{3}{4} [/math] is infinite.

This is wrong (since elements of [math] \mathbb{Q} / \mathbb{Z} [/math] have elements of finite order) and hence I think my understanding of quotient groups is lacking. Where did I go wrong?

>>8712881
in the quotient group you need to change
>Therefore the order of 34 is the smallest positive integer n s.t n∗34=0
to
>Therefore the order of 34 is the smallest positive integer n s.t n∗34=0 mod Z

and so n=4

>>8712887
I don't see why I should change from "n*34=0" to "n*34=0 mod Z". Adding "mod Z" doesnt seem to be consistent with the definition of order?

>>8705718
What kind of nootropics would you recommend for increasing intelligence and memory?
my main cap is bacopa monnieri, but I have feeling that you know a better nootropic.

where do you guys go to pull up works cited in your textbooks? im looking to follow up on something, but my university system just links me to a site that charges £70 for the fucker in ebook form, and its not even the exact publication cited.

>>8712099
utter crap

>imagine hypothetically that a distant historical event didnt happen
>bam, another time dimension
>b-but, what if you went even further BACK in history
>>bam, another time dimension

>>8705841
>Motion is an illusion
TheIllusionMeme.jpg

You mean "emergent phenomena". Stupid brainlet.

>>8712099
Best way to imagine 10 dimensions is this:

Imagine A boxes (1), that each contain B boxes (2), that each contain C boxes (3), that each contain D boxes (4), that each contain E boxes (5), that each contain F boxes (6), that each contain G boxes (7), that each contain H boxes (8), that each contains J boxes (9), that each contain K papers (10).

To specify any paper, you have to give 10 coordinates: A, B, C, D, E, F, G, H, J, K.

All other "scientific explanations" are just fantasy and romance. This is the easiest way to comprehend any amount of dimensions of any size with any relation to each other with any retarded complication you can imagine.

where can I find the rigorously stated axioms or proven theorems concerning what rearrangements are "allowed" with infinite series?

I often see people say things like "we need to be careful with infinite series because some rearrangements aren't allowed.

But I have never seen this formally stated or proven the way that for example in linear algebra the axioms of addition are stated.

Where can I find a complete set of axioms or theorems concerning which re-arrangements of infinite series are allowed?
I'm already familiar with the fact that an absolutely convergent series can be rearranged and no difference will be made to the final value, but that isn't the whole story. I want to know all the rules involved.

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I have a waveform with something that I suspect is frequency shift keyed data encoded inside. I have tried extracting via python script but no dice. What else could it be? Any help is appreciated

>>8713501
By the way, if anyone wants to give it a go, I uploaded the file to mixtape
https://my.mixtape.moe/ipiqit.wav

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What the fuck is the order of transforming an elementary function? Why the fuck is it the minus coefficient first, then additive +3 inside, then additive +1 outside AND THEN the numeric coefficient 2? WTF?! Why the fuck does it even matter? The fuck?

Please explain this moronic bullshit somebody shit out of their asshole on a chilly day.

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>just realised my coursework was due in yesterday
>pass mark will be capped at 40%
>had perfect grades up until now

What's the fastest way of killing myself?

Can someone critique my proof that the Cantor Set is closed? It goes as follows

One way to describe the elements of C (cantor set) is to say:

[math] x \in C \implies x \notin ( -\infty,0) \land x \notin (1, \infty)\land x \notin ( \frac{1}{3}, \frac{2}{3} ) \land x \notin ( \frac{1}{9} , \frac {2}{9}) ... [/math]

So a way to describe the elements not in C (as in the complement of C) would be


[math] x \in C^c \implies x \in ( -\infty,0) \lor x \in (1, \infty)\lor x \in ( \frac{1}{3}, \frac{2}{3} ) \lor x \in ( \frac{1}{9} , \frac {2}{9}) ... [/math]

So this complement can be written as

[math] C^c = ( -\infty,0) \cup (1, \infty)\cup ( \frac{1}{3}, \frac{2}{3} ) \cup ( \frac{1}{9} , \frac {2}{9}) ... [/math]

Which is the infinite union of open sets, which implies that it itself is also open.

But then, a set is open if and only if its complement is closed, so the complement of the complement of the cantor set is closed, so the cantor set is closed.

Is this okay? Can I do infinite logic like this? If I was in your topology class would you give me an A?

I can't determine max and mins of the function

$f(x)=\sqrt{1-x^2}+\sqrt{x^2-1}$

>>8713529
If you have it all done then just send an email saying "Hey i dun goofed but it's all done is there any thing I can do to fix this?"
As long as you don't present yourself as someone who just wanted more time/is a general slacker, you SHOULD be able to hand it in, even if it's penalized a little

>>8713546
Just take the derivative man, what the hell. Derivatives are a computational process. You don't even need to think.

>>8713557
>(
are you sure? look at the function

Why does nobody attempt to build a neural network that solves problems in the game "fold it"?

>>8713568
http://www.wolframalpha.com/input/?i=graph+sqrt%7B1-x%5E2%7D%2Bsqrt%7Bx%5E2-1%7D

I am looking at it.

I see two mins at 1 and -1 and I see a local max around 0.

>>8713578
>the function is defined in 0

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>>8713533
an infinite union of open sets is open

my proof would start at 'the complement can be written as...' but im lazy

i wouldnt give you an A because im a bastard

>>8713546
where is your function defined on?

>>8713609
\{-1,1\}

>>8713620
double check that m8.

I'm in my second programming course and I fucking hate it. I want to do something with life sciences and chemistry so I'm thinking either Biochem or biochemistry engineering. Is this a good degree?

>>8713624
where else?

>>8713632
A better question is: Where is it NOT defined?

Hint: for the whole function to be defined, both square roots have to be defined.

Are udemy courses worth it?

Just started continuous random variables. The first example the book gives is an experiment where one randomly draws a number X from the interval [0,1]. They define the pdf of X as

f(x) = 1 if 0 <= x <= 1, and 0 otherwise.

My question is, why define f this way, in particular, why equal to 1 if x is in that interval; I see why it is 0 elsewhere.

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How do you solve this pls

>>8713629
Idk about bioengy bit I would recommend not going with a chem, and especially not bio, degree if you don't plan on getting a Master's. Unless I suppose if you don't mind being a lab monkey. Have you taken a chem course with a lab yet?

>>8712960
>I don't see why I should change from "n*34=0" to "n*34=0 mod Z". Adding "mod Z" doesnt seem to be consistent with the definition of order?
because '0' is the identity in Q and in Z, while 'Z' is the identity in Q/Z

>>8713696
Wait I think I understand now. We're still assigning probabilities to events of the sample space (so R), and the event that x is in that interval has probability 1 (it's guaranteed to be in [0,1]). My book is not very rigorous in the slightest and didn't mention events at all, it just jumps into applications.

>>8713213
even if you do accept the many-worlds interpretation, alternate universes wouldn't be scifi bullshit like "this world except hitler never died"
they would be "this world except one specific electron collapsed from quantum superposition into an up spin instead of a down spin"

>>8713713
Weird problem. Where did you get it from.

But well, the first thing to do is notice that the left equation just says
sin(x) = 3/5

Multiply both sides of the equations together toget
sin(x)(cos(x) = 12/25
and multiply by two
2sin(x)cos(x) = 24/25
sin(2x) = 24/25

This will yield two solution sets (why is this?) and one of them will be the one you want, and the other will be one that is flipped. By that I mean that you get sin(x) =4/5 and cos(x) = 3/5.

We can safely ignore this second solution set and only use the one we care about:

[math] x = \frac{1}{2} (4 π n + sin^{-1}(24/25)), n \in \mathbb{Z} [/math]

Note: I used wolfram alpha and some by-hand checking of the solution set. The proof that what I say actually holds up for all n is left as an exercise to the reader. Also, finding wether or not this solution set contains all the solutions is also left as an exercise for the reader.

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What the fuck is the order of transforming an elementary function? Why the fuck is it the minus coefficient first, then additive +3 inside, then additive +1 outside AND THEN the numeric coefficient 2? WTF?! Why the fuck does it even matter? The fuck?

Please explain this moronic bullshit somebody shit out of their asshole on a chilly day.

>>8705971
Consider the prime factors and group them into tens and almost tens, should get you fairly close. N! >10^10

>>8713912
try rewriting your question into something comprehensible instead of spamming it every 30 mins

>>8713931
k how bout this

>What the fuck is the order of transforming an elementary function?

>>8713940
i said rewrite, not copy paste

obviously no one knows what you're talking about

try again in english

>>8713912
try doing the transformations in the wrong order
then you'll see you get a very different function

>>8713960
Try it you fucking retard and you'll see that it doesn't matter if you turn the fucking thing upside down and then multiply ordinates by 2 or the other way around.

>>8713977
baka you'll never make it brainlet

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anyone know why the fuck mathematica isn't plotting my function?

https://gyazo.com/837707b920fe7becad318ee07849b5af

>>8713988
nvm got it

how can mirrors be real if our eyes aren't real?

Bayes' theorem is p(a|b)= (p(b|a))*(p(a))/p(b) can it be restated as p(b|a)= (p(a|b))*(p(b))/p(a)?

>>8714101
of course

>>8714101
obviously... its just basic algebra

sorry, im trying to do a latex test
[latex]$a=b$[/latex]

>>8714105
>>8714107
Thanks. I imagined as much. I wasn't sure if these rules held for sets and unions.

>>8714115
kek

firstly there's a TeX button to display secondly there's a sticky with a link that you should look over

WHO USES ROOT HERE?

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How THE FUCK do you get what they get by adding two upper left expressions and multiplying them by the bottom middle one? It's fucking impossible. WTF?!

inb4: hurr use babbby high school proof - that's not the fucking point, autist

>>8714223
http://mathonline.wikidot.com/limit-product-quotient-laws-for-convergent-sequences#toc2

>>8705841
fuck off Kant no one likes you

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If we spent many years as a space faring race, would everyone become light skin?

Do particles have gravitational potential energy? Can a single hydrogen atom floating around in space have an inexplicably high mass just because it's on a perfect collision course with a blackhole two light years away?

>>8714239

I don't fucking get it. Are those typos when they write |a + A|?

>>8714306
>Are those typos when they write |a + A|?
obviously yes

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I was reading a book, "In praise of small digits", and I'm having some trouble understanding the proof for "The probability two numbers are coprime is 6/π^2"

My question is: Why/How can you expand (2.6) into (2.7), and how is the product in (2.7) equal to the sum at the bottom?

>>8714326
2.6 to 2.7 uses the geometric series. Try expanding 2.7 using 1/(1-x) = 1 + x + x^2 and compare to 2.6.
The denominator of 2.7 collects all possible products of primes uniquely (raised to power of two). Since prime factorisation is unique we can write 2.8.

>>8714326
https://en.wikipedia.org/wiki/Riemann_zeta_function#Euler_product_formula

How come the ratio of oxygen on earth is the right amount to sustain life? How does it stay stable?

>>8714256
probably not, unless occasionally needing to take vitamin D supplements was such a critical flaw that it actually caused space-age superhumans to have less babies

evolution doesn't intelligently decide to move in whichever direction's "best"
it is a very stupid and very random process

>>8712384
A TA helped me acquire the answer. Your answer was succinct, and correct, but it didn't help me. I threw together some LaTeX so ya'll can see how dumb I am.
[eqn] \lim_{x \rightarrow \infty } \frac{\sqrt{7 x^{2} + 1}}{9x-7}[/eqn]
[eqn] \frac{ (( x^{2} )(7+ \frac{1}{ x^{2} } ))^{ \frac{1}{2} } }{x (9 - \frac{7}{x} )} [/eqn]
[eqn] \frac{x}{x} \frac{\sqrt{7 + \frac{1}{ x^{2} } } }{9 - \frac{7}{x} } \Rightarrow \frac{ \sqrt{7} }{9} [/eqn]
Ain't that a pickle?

>>8714354
equilibrium through life cycles achieved through millenia of evolution

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Had this question on my Engineering: Statics test.

I asked my professor if the vector OA was in the XZ-plane, he said yes.

I answered the question with
theta X = 20 degrees
theta Y = 70 degrees
theta Z = 60 degrees

The correct answers were
theta X = 35.5 degrees
theta Y = 70 degrees
theta Z = 62.5 degrees

We were also given the Z component of the force F to equal 80lbs, and using that he created those answers.

I am having trouble intuiting how you can be both 70 degrees off the Y, and 35.5 degrees off of the X.

How to solve this without l'Hôpital's rule?

[math]
\lim_{x\to 0} \left (\frac{1}{t\sqrt{1+t}} - \frac{1}{t} \right )
[/math]

when making sure a point is at mechanical equilibrium, all points have to be at equilibrium, correct? So for instance you have to take the moments about all points into account?

>>8714535
>I am having trouble intuiting how you can be both 70 degrees off the Y, and 35.5 degrees off of the X
If OF was in the XY plane the angles would have to add to 90. But it ISN'T in that plane, it's a 3-d vector.

>>8714546
*a system is in mechanical equilibrium
sorry, im tired

>>8714308

Why the fuck is eB/4 smaller than e and 2Ae/B^2 smaller than e? WTF? They never explained this.

How much pee would i have to create to make the sun go away?

>>8714556
they never explain that because they never claimed either of those two statements

what specific step are you confused by?

>>8714539
graph it by hand

>>8714539
I tried using partial fractions but it was a lot of work so I gave up. I suggest you carry it out to the end but I'm not sure it'll result in a form that works.

>>8714650
I tried too but always got into a division by zero
I think I'm doing shit wrong, feels bad being a brainlet

is there any bad result of staying virgin for 20+ years? I never fap too.

Also, is there no books solely on group theory? its almost always inside a linear algebra books

>>8714679
there's tons of books on group theory, learn how to use the internet/the library/the google/the amazon search bar

Here's a stupid question: What does this code mean?
63837-46662-4483-968-87-638374

>>8714744
nuclear launch codes ,delete them ASAP

>>8714679
It can make it harder to get erect

>>8714773
i dont really care desu, i dont think i have the capacity to initiate sex to begin with

but does it have anyt effect on health? my psychology perhaps?

>>8705718
im poor and have nothing better, whats the best way to become a god at organic chemistry? I dont have access to education or a lab but im trying to learn.
What books can i start off with?

>>8714915

You tell me

>>8715022

If i have an experience of being anothjer person i can at least compare, is there no study out there polling the difference virgins and non virgins

>>8715060
are you distressed/depressed/mad about being a virgin or not
if it's not bothering you it's not an issue obviously

>>8705971
its negative infinity

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Why can I not do pic related? It seems logically sound to me.

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What melting temperature would metallic hydrogen have?
They claim it will remain a solid at room temperature but how much would we need to heat it up to reform it like with other metals?

Keep imagining it starting to boil, go back to normal hydrogen gas and explode.

And if you shot a portal at the surface of the moon what would happen if you shot the other into
>jupiter
>the sun
>a black hole

>>8715312
it is correct. If it can work with forces then it can work with acceleration

>>8714401
>evolution doesn't intelligently decide to move in whichever direction's "best"
This. The only reason why this seems to be the case is because of survival of the fittest

A spherical raindrop evaporates at a rate proportional to its surface area. Write a
differential equation for the volume of the raindrop as a function of time.

Can someone eplain why the answer is dV/dt = -kV^(2/3).

also another question

In each of Problems 1 through 6, draw a direction field for the given differential equation.
Based on the direction field, determine the behavior of y as t→∞. If this behavior depends
on the initial value of y at t = 0, describe the dependency.
1. y" = 3 − 2y

I dont get it because of the way its worded i think

>>8712960
You want a finite n such that n*3/4 + Z equals Z, which means that 3/4 has to be an integer, as a + Z is Z for any integer a.

>>8714539
Take sqrt(1+t) out, Multiply by 1+sqrt(1+t) in the numerator and denominator.

>>8715458
bump pls

>>8715541

dV/dt is proportional to surface area
surface area is [math]4\pi r^2[/math]
volume [math]V[/math] is [math]\frac{4}{3}\pi r^3[/math]
radius written as a function of volume is [math](\frac{3}{4\pi}V)^{1/3}[/math]
so surface area as a functon of volume is [math]4\pi ((\frac{3}{4\pi}V)^{1/3})^2[/math]
which is just some constant multiple times [math]V^{2/3}[/math]

we don't care what the constant multiple actually is because we're already multplying it the whole thing by [math]k[/math] to represent "some random constant we don't know or care about"

and [math]k[/math] is negative because [math]\frac{dV}{dt}[/math] should be negative -- the volume is decreasing

What is the correct method to use for doing collision detection among a fast moving particle system with millions of particles? This is luckily in a plane and not 3d.

Should I be doing quad trees or k-d trees? I have the logic of the simulation laid out correctly (probably) but now I need to implement collision detection and somehow get over 5fps realtime.

>>8715568
true that, i was thrown off by it being a rain drop (albeit spherical) and didnt even consider the surface area formula.

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>>8714639
Look.

Also I don't need alternative proof, I want to understand that specific segment of the proof >>8714223 - how did they manipulate absolutes to get |A/B - x/y| < eps

Cause I've tried every fucking thing in the book and nothing.

>>8715635
Also HOW THE FUCK do you get x < e + A from |A - x| < e?! That violates the absolute completely (absolutely).

>>8715635
you left out all the important parts of the proof you want explained brainlet, so obviously no one will help you w/o more details

in the alternative proof, since a_n and b_n converge we can find N big enough to ensure that:

|a_n-A|<|B|e/4 (equivalently |a_n-A|(2/|B|)<e/2)

and

|b_n-B|<|B^2/4A|e (equivalently |b_n-B||A/B^2|<e/2)

which gives, from the steps given in the proof...

|a_n/b_n-A/B|< |a_n-A|(2/|B|) + |b_n-B||A/B^2| < e/2 + e/2 = e

what is there to be confused by?

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>>8715647
> you left out all the important parts of the proof you want explained brainlet
Edited pic specifically for fucking autists.

>in the alternative proof...
That part is fucking clear. What I don't get is how IN THAT FUCKING PIC >>8715635

> |B|e/4 < e

>>8715667
its a typo you fucking moron, how braindead can you be?

its
|a_n-A|<|B|e/4 (equivalently |a_n-A|(2/|B|)<e/2)

can you not think with your brain for once in life?

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>>8715667
also its fucking baby high school math, if this is that difficult for you just drop out before you get even further in over your head

>>8715670
What sort of fucking typo is that? What did they mean by |a_n-A|<|B|e/4<e/2? Clearly the middle is not smaller than the right part.

>>8715672
Try doing it you fucking moron and see that it's impossible. Of course you're all talk and no walk. All you're good for is shitposting in sqt thread pretending to be above everybody when clearly you can't even figure out basic absolutes.
It's not hard to post some shitty links to retarded 20 yo sites with 10000 fucking mistakes. My fucking mouse would've done a better job.

>>8715685
>Of course you're all talk and no walk. All you're good for is shitposting in sqt thread pretending to be above everybody when clearly you can't even figure out basic absolutes.
>It's not hard to post some shitty links to retarded 20 yo sites with 10000 fucking mistakes. My fucking mouse would've done a better job.
you're the one not able to understand multiple proofs of an easy claim that takes about 5 lines of math

i feel no need to rewrite such a short argument since if you can't understand how it's been presented to you already (TWICE) then you're obviously just a brainlet.

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>>8715689
I understand every part of every proof you unintentionally funny cum container. But clearly there's either some obscure trick or a typo in this pic because you cannot get what they get from what's given. And if you knew what it is, you would've posted it already. But of course you are clueless.

>>8715693
>. But clearly there's either some obscure trick or a typo in this pic because you cannot get what they get from what's given. And if you knew what it is, you would've posted it already. But of course you are clueless.
god you're retarded

like i already said several posts ago, you left out all the important parts of your proof that are needed to answer your question

so why don't you post the rest of the proof so someone can point out the blatantly obvious thing that you're too stupid to understand?

or just keep posting the same thing over and over again and expect things to magically work out, that's fine too

13 / 5 = 2 and remainder 3
this is logical.
13 / (- 5) = -2 and remainder should be 3, because -2 * -5 = 10, and 13-10 = 3.
but apparently the result is "-2"? explain.

the reason i'm even thinking about this is because i thought all remainders have to be positive, and so it could explain why division by 0 is impossible (because division by 0 would result in invalid remainder classes)

>>8715700
>but apparently the result is "-2"? explain.
why?

the remainder is 3 just like you said, since 13=(-5)(-2)+3

>>8715699

I honestly cannot believe how fucking dumb you are. What part about ADD this to that AND THEN MULTIPLY IT by that to get THIS do you not understand? The operation I draw should produce the result in the bottom of the fucking page.

>>8715703
i entered 13 mod (-5) into wolfram alpha, the result is -2.

>>8715708
3 is equivalent to -2 mod 5...

>>8715707
>>8715707
god you're fucking dense

its very clear if you're not a brainlet that |xn| (1/yn^2)Delta(y_n)+|1/yn|Delta(xn) does not produce |A/B-xn/yn|

this is because EARLIER IN THE PROOF this sum is related to |A/B-xn/yn|

but you STILL DONT POST THE REST OF THE PROOF because youre a fucking brickhead

What part of THIS do you not understand?

>>8715709
really makes you think

>>8715713

Jesus fucking Christ.

I became so obsessed with the absolute tricks that I forgot about the fucking premise of the proof.

Thank you kind anon.

>>8715717
Go fuck yourself, dude.

I need help with this word problem:
10 armed psycopaths convene in a room.
At the word "go" they all simultaneously shoot a random other person.
This is repeated with the survivors until either everyone is dead or only one remains.
What is the probability of each end state?

>>8715842
Letter them all and map the possibilities of each shooting one of the others and then count the probability

They would be A, B, C, D, E, F, G, H, I and J

"A-B" for instance means A would shoot B, and all the other possibilities of who he can shoot

Just repeat with each

A simple but a large-scale question:

Does the total number of atoms in the universe change?

>>8715842
I'm trying to picture the situation. Let's say you have people A to J.
Let's look at one extreme case: everyone chooses the same person: J. So everyone shoots at J, except J, because he has to shoot "a random other person", so he will choose I. So J and I die.
Based on this, i think 2 people die in every round.
So if there's 10 people, shouldn't it be impossible for 1 person to survive?
i could be wrong though

>>8715864
>2 people die in EVERY round

2 people may die, but not necessarily.

It's a possibility that they all die in one round, imagine they stood in a circle facing the same way and everyone shot the person in front of them

>>8715852
wouldn't this be some unimaginably large number of possible combinations? surely there has to be some formula or rigorous mathematical way to calculate this.

>>8715842
Obviously, you'd simplify it using symmetry. E.g. if M people are alive, it doesn't matter which M people they are, and the probability of N people being alive at the end of the "round" doesn't care about which N people.

So it's essentially a case of determining the probability matrix: given N people alive at the start of the round, what's the probability of M people being alive at the end of it, then using that to calculate the probability of a given number of survivors after a given number of rounds, then summing the probabilities of each final state (zero or one survivors) from an initial state of ten people.

There can be at most nine rounds (at least one person dies each round, and a sole survivor has no-one to shoot), but may only be one. Each final state can occur after any number of rounds. The probability matrix doesn't depend upon the round number.

The definition of "each end state" is unclear. If different sole survivors are different end states, then just divide the probability that it ends with one survivor by ten.

Might be related to Markov chains (transition probabilities).

>>8715842
Edgeeey!!!

Do you have to say the word "psychopath" every fucking time you talk about something """""""""""""""""""""""""""""""""""""""""""wrong"""""""""""""""""""""""""""""""""""""""""""""""?

Nice.

What protractor do you use?

If quantum particles can randomly move faster than c, what prevents them from violating causality in a setup that tries to get a particle to cancel out its own creation for situations where it jumps past c?

>>8715874
It relies on several rounds AND on a random possibility of who gets shot, or how many people get shot

If there are different outcomes or ways to progress to the same outcome there can hardly be any formula

If it was only one round, it would be exponentially more simple

>>8715963
it seems like there should be some way to do it using the inclusion exclusion principle, but I'm not sure how

Anyone know if you can reference specific cells inside integral functions in excel?

Like "=G11", the number doesn't show up in the upper bound, just =G11.

>>8715842
I tried working this out for simpler cases, looking for a pattern in the probabilities of no survivors:
0 persons: 1
1 person: 0
2 people: 1
3 people: 1/4
4 people: 11/27
5 people: 17/32
6 people: ???
I don't see any obvious pattern

>>8715842
Consider n number of psychopaths. Assume that 'k' people die in the first round. So we choose k people.

Probability that a zero-survivor event occurs given that k people dies in the first round is equal to (nCk)*Z(n-k)=Q(n-k), where Z(m) for all natural numbers m is the probability that a zero-survivor event occurs given m psychopaths.

k is at least 2 and at most n, so Z(n) equals summing Q(n-k) from k=2 to n. I've no idea how to proceed further to solve this recursive function.

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>>8707974

I need to write a Bachelor thesis, but i haven't been "accepted" by a department/faculty yet. What do i do if nobody wants to let me write a bachelor thesis at their department?

>>8713728
My uni offers a biochem engineering degree. I'm thinking about that for sure. I have taken a Chem with lab and I love it. However, due to programming it was never my first priority so I couldn't really focus.

>>8716026
>k is at least 2 and at most n, so Z(n) equals summing Q(n-k) from k=2 to n

shouldn't this be a weighted average though?
2 people dying or n people dying are going to be less likely than numbers closer to the middle

new thread when?

>>8716383
48 hours after this one dies

>tfw brainlet
pls save me
f[(x^3) - 8] = 4x^2
f'(0) = ?

>>8715568
Anon needed to show that [math]\frac{dV}{dt} = -kV^{2/3}[/math], which means that [math]k > 0[/math].

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https://youtu.be/CnMrf9aW-LU?t=15m54s (third line, 15:54)
I don't get the (14/9), someone can find it please ?
I hope the writing is clear.

>>871653
The final goad is find the GCD. *

Why is /sci/ always studying?

>>8716555
You mean shitposting? I wish was studying

>>8716560
Lot of students here

>>8716502

can't you just substitute x^3 - 8 into 4x^2 to get 4(x^3 - 8)^2, then differentiate and solve em?

>>8716531
the left side is equal to the right side.
look at the first part of the right side. (3x^3 + 2x^2 +5x -2 ) * (1/9) * (3x+4)
if you calculate that, it's x^4, 2x^3, and (23x^2)/9, and (14x)/9 and (-8/9).
Now look at the right side, the - 14/9 * (x^2 + x + 2)
calculate that, and you get -14/9 x^2. etc.
(23/9)x^2 - (14/9)x^2 = (9/9)x^2 = x^2 which is also on the left side.
basically, the left side has to equal the right side, and if you solve the brackets it fits
but if you ask me how he ever managed to get to the 14/9, i have no clue

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WHat would the B-field of a looped wire where the wire is a solenoid all the way around look like?

>>8716606
If you write the question in a general form wouldn't it be
f(g(x)) = h(x)
Doing what you say would give us the derivative of h(g(x)) which I can't see as being equal to f'(x) (maybe it is but I dont know how to prove it)
My approach was to try to find f(x) then differentiate that, but it's not working out for me

>>8716762
what if you just differentiate x, then solve x^3 -8 = 0 ? then assign the values
¯\_(ツ)_/¯

>>8716762

the notations seems to be fucked up to me, like if i write f(h) = 4x + 2 it wouldnt make fucking sense right? its the same thing here, if i take x = 2, what the fuck is is f equal to now?

depending on the answer, that is how you differentiate them.

>>8716859
I solved it my way,
f(x)= 4x+32 / (x+8)^1/3
I took the derivative of that and plugged in 0, answer was 1.333

I don't understand what you're suggesting though, you get x=2 and then what?

Does quantum mechanics allow particles a small chance to hit a detector before the particle was even chronologically created?

>>8716890
first solve f', you get f' = 8x

then solve x^3 - 8 = 0 to get x = 2 as you said, then just do f'(2) = 8(2) = 16

how did you even arrive at f(x) = (4x + 32) / (x + 8)^(1/3) ?

>>8716913
I don't think you're right
if f(x^3-2)=4x^2
that does not mean f'(x^3-2)=8x

say f(x) = x^2
f(5) = 25
f'(5) = 0
this is obviously incorrect, since f'(5) = 10

My method:
f(x^3-8) = 4x^2
that means f(x) is a function that takes x^3-8 as an input and spits out 4x^2
I worked backwards to determine that function, which is 4x+32 / (x+8)^1/3
Now that I know what f(x) is, I can simply differentiate it and plug in 0 to get my answer, which is 4/3 or 1.333

>>8716948

i see, that method is new to me

thanks anonymous friend

For a flip flop, what happens to the output if one of the inputs changes just as the clock changes?

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I'm stuck on Theorem 5 and Theorem 6 (though haven't put as much time into it as 5)

Please help a fellow brainlet out, they don't release the solutions to these for some retarded reason

>>8717166
remember definition of convergence

>>8717173

if {a_n} is convergence, then for every e > 0 there exist n > N where |a_n - L| < e

we have b_n = a_2n and since 2n > n > N then b_n must also converge

it all comes down to the fact that the sequence b_n and c_n takes the terms ahead a_n for any n.. right?

let say we have b_n = a_(n/2) all of these theorem is false right?

how is it possible to apply kleene star on an empty set V? the concentation of xy, where x = e and y E V, but there's nothing in V, nothing as in y doesnt even exist