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/sci/ - Science & Math


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9902922 No.9902922 [Reply] [Original]

stupid questions thread / QTDDTOT

ask all your brainlet questions that definitely don't deserve their own thread

>> No.9902940

Is this the stupid questions thread?

>> No.9902970

If you’re a student in the top percentile for science and math, will you earn in the top percentile?
Or even anywhere near that, assuming you maintain your grades?

>> No.9903535

>>9902940
is this a rhetorical question?

>> No.9903701

I asked this to /fit/ but got no responses so I assume they don't know. Maybe you guys do.

Does physical exertion burn a static amount of calories or does it change from person to person? Say for instance you bench press 150lbs a single time. Would a strong guy who has no trouble burn less calories than the average joe who could barely manage? Because to lift that bar would require a specific amount of force against gravity so is the energy needed to supply that force quantifiable into a static caloric amount?

>> No.9903705
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9903705

the supremum is obviously 1, and its easy to show 1 is an upper bound of B, but im struggling with showing that its the least upper bound. I'm going about it by trying to show that for any number less than 1 you can find an element of B greater than it, but that fact that its a set of discrete points not a continuous interval has me stumped, any help is appreciated

>> No.9903832
File: 10 KB, 477x95, binomischerLehrsatz.png [View same] [iqdb] [saucenao] [google]
9903832

can someone explain this step to me? Is this Vandermonde's identity?

>> No.9903842

>>9902940
nice

>> No.9903848

Given A IMPLIES (B IMPLIES C) : deduce (A AND B) IMPLIES C

>> No.9903858

>>9903705
It is pretty simple. As [math] A [/math] is unbounded, choose a sequence [math] (a)_n [/math] such that [math] \lim_{n \to \infty} a_n = \infty [/math]. Then [math] \lim_{n \to \infty} \frac{a_n}{1 + a_n} = 1 [/math].

Now, if you assume that there exists an [math] x < 1 [/math] such that for all [math] a \in A, x \geq \frac{a}{1+a} [/math] then for all [math] n [/math], [math] 1 > x \geq \frac{a_n}{1 + a_n} [/math]. Now take the limit as [math] n \to \infty [/math] which yields [math] 1 > x \geq 1 \implies 1 > 1 [/math], a contradiction.

>> No.9903860

>>9903848

~ a or (~b or c)
~(a and b) or c
(a and b ) -> c

>> No.9903866

>>9903705
>>9903858
Oh, by the way, if you are doing this for a really basic real analysis class, if I was you I'd also write down why such a sequence exists in the first place. It is obvious but I leave that as an exercise for you.

>> No.9903891

>>9903705
>but that fact that its a set of discrete points not a continuous interval has me stumped,

it's no different. take A as the set of positive reals and do a usual epsilon-delta proof. since A is unbounded, there will always exist some a in A that's bigger than the minimum value you need for a.

>> No.9903984

>>9903860
Can this be done without negation? Or more generally, is it possible to convert any given logical proof that uses negation to an equivalent one without negation?

>> No.9903992
File: 64 KB, 580x583, 2018-07-30_18-44-50.png [View same] [iqdb] [saucenao] [google]
9903992

I understand the part with Gamma_(N+1) (s)/Gamma_N (s) = the two sums, but how does it then equal the next bit with (1+s/N + O (1/N^2)) * ..., and what the fuck is O? It's nowhere mentioned before.

also
>inb4 german

>> No.9904018

>>9903992
O as in Big O notation. [math] \left( 1 + \frac{1}{N} \right)^s = 1 + \frac{s}{N} + O(\left(\frac{1}{N^2} \right) [/math] is true by the binomial theorem.

>> No.9904024

>>9904018
thanks!

>> No.9904039

>>9902922
How could someone get a nuclear powered space station to work without causing heat to murderfuck everything on board
what sorts of radiator systems would be required?

>> No.9904121

>>9903984

from a,b, a->(b->c), apply modus ponens twice to prove c is true whenever a and b are true.

>> No.9904184

>>9903984

and yes, i think so. modus ponens is the only rule of inference in some axiomatizations of propositional logic, so if you replace ~a with (a->F) and proceed as usual then you can write proofs without explicitly using negation but this is only a difference in notation

>> No.9904254

>>9903701
the bigger your muscles / "stronger" you are, the more elastic energy is stored in your muscles. In particular, the easier it is to lift 150 lbs. That is, your body is more efficient at lifting the bar and hence you require less energy, and hence you burn fewer calories. That is why you want to keep increasing the weight you lift too.

>> No.9904259
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9904259

Why is the red marked reaction faster?
When I compared both reagents, Oxygen is more electronegative one.
Shouldn't i hvae applied ARIO on it?
Atom properties
Resonance
inductive elements
and orbitals?

>> No.9904260

>>9903832
nigga just write down the fractions of both binomial coefficients, simplify and see what happens. did you even try lmao?

>> No.9904334

what is Langans CTMU about?

>> No.9904347

1) How does electron or other particle realize that he is watched?
2) There is a problem with connection of gravity and electromagnetism. Newton's law of universal gravitation looks similar to Coulomb's law. Is it considered somehow? How?

>> No.9904386

What is the least popular field of science?

>> No.9904830

Explain to a complete retard what the fuck is electric potential and electric potential energy, what they do in a real life situation and what is the difference between the two concepts. No physics notations like "V = U/Q"as I can find it in the textbook.
Thanks!

>> No.9905046

Taking Abstract Algebra this semester, any tips?

>> No.9905082

>>9904830
Electric potential is basically the amount of energy you need to use to move charged particle from point A to point B in electrical field.
The best analogy to real life is to think about magnets, because in concept level electrical force is similar to magnetism - just change positive/negative charge to south/north pole and electrical potential to magnetic potential.
If u take any two magnets, even the weak shit for the fridge, and try to combine them with same pole facing eachother (with both negative/positive charge moving into each other), you will find that it's very hard to do it cleanly, if you are able to do it at all. It's because the closer they get, the magnetic field gets stronger, so you need to do more work (in Joules) to do so. If you aren't able to combine them because they just push eachother to hard, you have found the potential barrier.
I've fully understood this when teacher explained for thermal fusion in the Sun works.
The atomic nucleus are positively charged, so it's impossible for them to combine and create heavier element by normal, chaotic movement inside the sun, at certain distance they repel each other to hard, so electrical potential is high. They way thermal fusion works is because of the random "teleportation" of particles, so they can "jump over" the potential barrier and get infinitely close to each other, therefore combine and create new element.

>> No.9905105

>>9902922
I want to get into machine learning using python. What resources would you recomend?

>> No.9905217

>>9905082
> The best analogy to real life is to think about magnets
I'd suggest gravity. Potential = height. Potential energy = height * mass = the amount of energy required to move an object uphill = the amount of kinetic energy it will acquire if you let it roll downhill.

>> No.9905249
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9905249

>taking calc 2
>cant just rely on geometric intuition

what do i do boyos?

>> No.9905458

>>9902922
I know this is such a brainlet thing to ask, but when doing ε-N, ε-δ proofs, I can do the simple ones, but I still have problems in choosing my deltas and finishing proofs. Can anyone help me?
Like for example, proving that a sequence is continuous, I can understand the proof if I read it 100 times but I just can't come up with a proof by myself (which indicates I don't understand the subject yet)

Say this question, if
[math] \lim_{x \to \infty} a_n = α [/math]
then prove
[math] \lim_{x \to \infty} \frac {a_1 + 2a_2 + ... +na_n}{1+2+...+n} = α [/math]

I have tried to prove it many times but I just can't, plus my book is written in japanese as I am studying in Japan, so my analysis course is in japanese and I want to kill myself.
Thanks for the response and sorry to bother you.

>> No.9905839

>>9905046
it's gonna be hard.

practice practice practice

>> No.9905861

>>9905458
that question is just really tough. you should concentrate on solving it heuristically, then once you've done that, work out the details of the epsilon deltas. Also note that you will usually need to choose your delta retroactively

>> No.9906029

Does anybody have "Ohanian, Hans C. Physics. Vol. 1. 2nd ed., expanded. New York, NY: Norton, 1989. ISBN: 9780393957501" as a pdf?

>> No.9906045

>>9905249
Develop symbolic intuition.

>> No.9906050

I have a BSc in Biochemistry. Can I put BS in Chemistry?

>> No.9906106

Whats the difference between a psychologist and a psychiatrist

>> No.9906132

anyone got any study tips? I've started using highlighters and color coding with pens, also sticky notes & tabs but other than that anyone got and tips for retention or just methods of study? right now I'm pretty much just doing bullet points - is it worth learning to do mind maps

>> No.9906134

>>9906106
psychiatrist has medical and mental health training and can prescribe medication, psychologist has a psychology degree and cannot prescribe medication
webmds pages is pretty good
https://www.webmd.com/mental-health/features/psychologist-or-psychiatrist-which-for-you

>> No.9906293
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9906293

Does this look roughly right? Initially used the 20v peak but built the circuit in a sim and it seemed to calculate the voltage drop from the resistor and said 18.9v. How do I calculate the voltage drop without knowing the current? Am I meant to just use the 20v val?

>> No.9906520

>>9902922
Can anyone tell me if "coding boot camps" are worth the time?

>> No.9906544

>>9906520
only if you put the work in, and also you shouldnt put you've been to one in your CV

>> No.9907082

In space can you see your own hand in front of your face? Are the stars bright enough for that?

>> No.9907083

>>9906106
Psychology is the study of the mind. Psychiatry is the branch of medicine for treating the mind.

>> No.9907112

>>9907082
If you're near Earth, but not behind it, then it's about as bright as daytime equator.

>> No.9907162
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9907162

Does anyone else here start fucking up on math problems after working through problems for 6+ hours in a day? If so, have you found a way around this?

After about 5:00-6:00 I'm pretty much useless as far as math goes. I've been able to plan my course schedules around this, but in the event that I can't, what do?

>> No.9907389
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9907389

How the hell they did it?

>> No.9907390

>>9907162
take more/longer breaks during your 6 hours

>> No.9907397
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9907397

this is coming from my trig course.
I have no idea how I'm supposed to find the roots.
They're not equations, not functions, and there are no variables

we didn't cover problems like these during the lectures. Can someone point me in the right direction?

>> No.9907399
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9907399

>>9907397
I've tried this on #11, but considering it's a basic problem and it's asking me to take the cosine of 15 degrees and still find an exact answer, I don't think this is how I'm meant to solve it.

>> No.9907409

>>9907399
cos(15) = cos(45 - 30)
You are welcome.

>> No.9907415

>>9907399
>>9907409
Oh, wait. Now that I think about it, there is an easier way. Notice that [math] (a+b)^2 = (a^2 - b^2) + 2abi [/math] so you have to solve the system [math] a^2 - b^2 = 2 \\ ab = \sqrt{3} [/math]. But the solution is apparent, take [math] a = \sqrt{3}, b = 1 [/math] to get the square roots [math] \pm( \sqrt{3} + i) [/math]

But computing cos(15) will give the same solution.

>> No.9907488

>>9907415
>>9907409
>>9907397
I hate my life I wasted an hour and a half on this one problem because I mistakenly wrote 30 degrees instead of 60 degrees and now the answer is trivial

where can I elect to sterilize myself

>> No.9907497

>>9907488
>hour and a half
>one problem
Are you for real? Like, I give actual olympiad problems much less time. Literally, if I haven't made any progress in 30 minutes I read the solution. Fuck that noise.

>> No.9907512

>>9907497
it was probably closer to an hour
I have dyscalculia and I made a copy error writing 30 when I meant 60. I didn't pick up on the copy error for an hour.

>> No.9907515

I'm really waiting for trinary to come out, did you dumb nerds do anything yet?

Where is the portal?

>> No.9907517

>>9907512
Well, that is more common than you'd think. You really just have to invest some time into proof-reading and learning a couple of quick methods to check your solutions are correct. In this case, it is pretty simple, whatever you get square it in your mind. If it doesn't give the solution, you fucked up somewhere along the line. It shouldn't take much to slowly go through your steps one by one.

Is Dyscalculia like real? Like, do you take drugs for it?

>> No.9907518

Nicholas cage, did you find the missing piece?

>> No.9907528

>>9907517
there's really nothing you can do about it, but yeah it's real.
the problem is I can go glacially slow and I will still make those mistakes, that's just what it does to me, among other stupid bullshit. It's not that I'm careless, I genuinely don't notice the errors I'm making until it's far too late

calculus is going to be fun

>> No.9907543

>>9907528
Well, you should be grateful that computers do everything today anyways. You just need to know the theory. You'll just have to survive college.

>> No.9907861

How would this be written as an equation?

I am currently going one mile an hour; In eight hours, I'll have accelerated to two miles an hour; Four hours later, I'll have accelerated to four miles an hour; Two hours later still, I'll have accelerated to eight miles an hour; An hour later still, I'll have accelerated to sixteen miles an hour.
Basically, doubling my speed in half the time it took me to double my speed previously.

>> No.9907862

>>9907861
Is your speed smooth or do you double your speed suddenly on the hour?

>> No.9907863

>>9907389
the power of capitalism

>> No.9907866

>>9907082
The sun makes space extremely bright.

>> No.9907922

>>9907862
Smooth, but if it's easier to write the latter way that's perfectly fine!

I've also been trying to fucking post for the last half an hour but the captchas keep saying I'm wrong, god damn

>> No.9907935

why my peepee hard

>> No.9908019

>>9907861
[eqn] \dot{x}(t)=\frac{2}{2-\frac{t}{8}} [/eqn]
once you get to 16 the speed will be infinite so the equation gets rather crazy

>> No.9908034

Why does the antiderivative correspond to the area encircled by the function?

>> No.9908071

>>9908034
The idea of integration is approximately to find the area of successively smaller trapeziums under the curve and then add them all up. The area of the trapezium depends on the height of the function and on the slope of the trapezium, and the latter is precisely why you need the antiderivative: to best represent the area, you would want to know the slope of the trapezium at every point

>> No.9908104

>>9908071
Okay, but then why do we need the antiderivative? Can't we generate trapeziums using thr data we have available in the form of the derivative and the function itself?

>> No.9908339

>>9908104
just look at wikipedia

>> No.9908750

>>9904347
>1) How does electron or other particle realize that he is watched?
observed means that it was interacted with, which means something was made to collide with it (particles)
>2) There is a problem with connection of gravity and electromagnetism. Newton's law of universal gravitation looks similar to Coulomb's law. Is it considered somehow? How?
How is that a problem? Also I don't know the actual reason if it even exists, but I'd guess it's due to both photons and gravitational waves being (rest-)mass-less. In particle physics you have something called the Yukawa-Potential, which means that for mass-possessing exchange particles the potential is closer to [math]\frac{e^{-\kappa r}}{r}[/math] with [math]\kappa = \frac{Mc}{\hbar}[/math]

>> No.9908852

1. Are there any universities in North America or Europe that are right-leaning?
2. Do any of them have decent STEM programs?

>> No.9909025

>>9908852
>1. Are there any universities in North America or Europe that are right-leaning?
In the US - all the religious ones. In Europe - not as you'd define "right-leaning".

>2. Do any of them have decent STEM programs?
No.

>> No.9909185

>>9909025
>In Europe - not as you'd define "right-leaning".
I've heard of something like this. If I'm not mistaken, Germany technically has a conservative government, but they're essentially democrats in practice.

>> No.9909345

>>9907162
Watch this: https://www.youtube.com/watch?v=IlU-zDU6aQ0

TL;DW: When you start to slip, take a short break to increase overall studying efficiency.

>> No.9909367
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9909367

Can someone explain the point of derivatives? Maybe I'm looking too deep into it, as I already have a general gist of differential calculus.

I know if for ex. you've got a time vs position graph, if you take the derivative you can find out the change in position for some change in time at some time t. But what does that mean? Does it mean at t=15s, if the derivative is 4, that if one second were to pass, the position would change 4 meters?

>> No.9909380

>>9909367
yes, if you were to continue at that speed you would be moving at 4 m/s

>> No.9909399

Let [math] r_{i} [/math] be a rectangle with area [math] a_{i} [/math],
[math] s_{i} [/math] be the set of the lengths of the sides of [math] r_{i} [/math],
[math] r_{ i \leq n } [/math] be the set [math] \{ r_{i} : i \in \{ 1,2,3,...,n \} \} [/math] and
[math] c [/math] be a function from [math] r_{ i \leq n } [/math] to [math] \bigcup s_{ i \leq n } [/math] such that [math] c( r_{i} ) \in s_{i} [/math].

Given [math] r_{0} [/math] and [math] r_{ i \leq k } [/math] such that [math] \sum a_{ i \leq k } = a_{0} [/math] and there is some [math] r \subset r_{ i \leq k } [/math] such that [math] \sum_{ r_{i} \in r } c( r_{i} ) = c( r_{0} ) [/math]. Is it always possible to tessellate [math] r_{0} [/math] with [math] r_{ i \leq k } [/math]?

In non autistic math terminology:
Given a big rectangle and some small rectangles such that the sum of their areas equals the area of the big rectangle. Assuming we can arrange some of the small rectangles such that their sides perfectly cover one side of the big one, is it always possible to perfectly cover the big rectangle with the small ones?

Question #2: What branch of mathematics deals with questions like this?

>> No.9909400

>>9909185
"Liberal" means the opposite in most of the world, set against what it means in the states - and many of our other political terms are kinda inverted as well.

Though, even by the US definition, most of Europe is left of the Democrats.

>> No.9909407

And are there similar formulas for strong and weak interactions? I mean, similar to gravitation and electromagnetic laws - with linear functions on "charges" of interaction and quadratic on distance^(-1)?

>> No.9909409

>>9903705
One simple thing you can check for is monotonicity. The map a -> a/(1+a) is monotonically increasing, so it is a fundamental fact that its supremum is equal to its limit. The proof is easily modified in this case, because you are allowed to choose 'a' arbitrarily large.

>> No.9909419

>>9909407
not really. Generally they follow Yukawa-Potentials as I said >>9908750
but the big thing is that strong and weak force have multiple types of carriers. Strong force has 8 types of gluons, weak has [math]W^{/pm}[/math] and [math]Z^0[/math]. And the strength and reach depend on their masses and type

>> No.9909432

>>9909367
The derivative would give you the speed you are going at that instant in time. It's like checking the speedometer. You could be accelerating rapidly during that time so you can't say how far it would take you in 'x' time afterward. But it gives an approximation if you are talking about a small time afterward.

>> No.9909445

>>9909367
Forget that shit about time.

Take this sentence to heart:
>The derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value).

Basically it is for Analyzing Function Behavior.

(Based on minute differences.)
You could even take "discrete derivatives" of functions with fixed steps. Like monthly profits.

(in thousands) d $/ d month = ($[x+1] - $[x])/ (1 month)
(1) (2) (3) (4)
10 15 7 8 -> monthly revenue
5 -8 1 _ -> momentary velocity of money accumulation ($/month)
-13 9 _ _-> momentary acceleration ($/month2)

>> No.9909494

>>9909399
Interesting thing, like it is from olympiad or something...

I remember the similar problem with inverse question (the bigger fugure is tesselated already). The solution makes use of orthogonal projections of sides of rectangles in the hypothetical tesselation, to the side of the big square (rectangle, in your case).

http://www.problems.ru/view_problem_details_new.php?id=107858
(russian site, need GTranslate)

May be this one can be done with a similar method.

>> No.9909807

>>9909494
>like it is from olympiad or something
Nah, you're giving me too much credit. Anyway, if you were wondering, the rectangles with dimensions 10x5, 6x1, 4x2 and 9x4 are a counter example.

>> No.9909881

>>9903705
In my experience, supremum and infimum come before sequences, so here's a solution using only properties of the reals. Let [math] b < 1 [/math] and take [math] a > \frac{-b}{b-1} [/math] (which you can do because A is unbounded). Then it's easy to show [math] b < \frac{a}{a+1} < 1 [/math] which proves every number smaller than 1 isn't an upper bound of B. Be careful when handling the inequality because [math]b-1 < 0[/math].

>> No.9910558

When something like a magnet and a bearing ball pass each other in a vacuum at zero G, there's this effect by which the greater the difference in their relative velocity, the less their trajectory is curved towards each other. I'm not sure where I heard it but this effect has a name I can't remember, does anyone know what it is?

>> No.9910603
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9910603

any help with either of these two questions would be appreciated

for the first one, I think the way to go about it is by showing that the supremum of A and the infimum of B are the same thing, but i dont know how to formalize that, showing uniqueness should be easy enough once that is done though

for the second, i can understand intuitively what is going on, that the k sequence is increasing in the naturals, so that the behaviour of the a sequence when "indexed" by k remains the same in the long term, but again, i dont know how to formalize that notion

thanks lads

>> No.9910638
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9910638

What is a definite integral over a hypercube of edge length 2 L?

>>9910603
Dude, just read this instead: http://homepages.wmich.edu/~drichter/octonions.htm#hammi

>> No.9910664

What's a good way to learn Java if you have zero knowledge about coding?

>> No.9910670

>>9910664
Pretty much learn how to 'hook events'.

{data-object}.onClick('left click', performThis(){
You left clicked on the data-object this code described!
})

>> No.9910720

>>9910603
for the first note that any b is an upper bound for A. Use this to show that for any a, a<= inf B, which exists and is unique thanks to the completeness of R. Then, show that inf B=supA by showing that inf B is an upper bound of A and then showing that for any number higher than inf B, there is a lower upper bound of A.

I don't know if you've seen it yet, but any subsequence of a convergent sequence converges to the same limit. Note that the definition of a subsequence necessarily implies infinitely many terms. What the condition of the second question is saying for k_n is that the sequence k_n has infinitely many terms, since no natural number is such that 1/n = 0. This means that k_n is a proper subsequence of a_n, and in particular must converge to L.

>> No.9910721

>>9910603
Since B is bounded below then inf(B) exists and you can take r<inf(B). Since the rationals are dense on the reals, there is some rational q such that r<q<inf(B), therefore q is in A, which implies inf(B)=sup(A).
However, that's assuming the existence of the supremum and I don't think you're supposed to do that but actually prove its existence using your construction of the reals.

For the second one, I recommend you read up on subsequences. What the problem is asking is basically to prove every subsequence of a convergent sequence also converges to the same value. You'll have to give an epsilon-M argument to prove this.

>> No.9910729

>>9910720
>>9910721
ive actually cropped out part of the second question that says not to use subsequences, its why i was struggling, its from a tutorial and we've not covered subsequences yet

>> No.9910770

>>9908852
If you're going to or avoiding an institution of higher learning because of its political leaning, then you do not belong in an institution of higher learning.

>> No.9910864

>>9910729
there's no escaping subsequences in that question because a_k_n is literally a subsequence on a_n whether you like it or not. You can either prove it without mentioning subsequences although youre implicitly using them, or mentioning them, but the end result is the same

>> No.9910924
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9910924

>>9910729
Very well. Then excuse my handwriting but I don't feel like fighting 4chan's broken latex.

>> No.9910947
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9910947

I’m getting into the area formula for circles and I keep getting completely different answers for some problems but getting some of them correct like...
>π=3.14 r 2=8
>3.14 x 8 x 8=50.24
I keep getting 200.96 everytime I calulate it myself or use a calculator with this problem.

>π=3.14 r 2=60
>3.14 x 60 x 60=11,304
This one however, I got correct.What do?

>> No.9911077

>>9910947
>π=3.14 r 2=8
Is 8 the value for r or for r^2?
If it's for r, then π*r^2 = π*64 = 201.062.
If it's for r^2, then π*r^2 = π*8 = 25.133.

>> No.9911081

>>9910947
>>3.14 x 8 x 8=50.24
lol

>> No.9911149

>>9911077
I believe it’s 8^2, this shits giving me a headache.

>> No.9911329

>>9909367
look up 3blue1brown's video series on calculus, he puts it in words nicely

>> No.9911359
File: 37 KB, 375x500, Uck3.jpg [View same] [iqdb] [saucenao] [google]
9911359

>>9910558
Okay, I'm gonna put this another way.

Suppose an asteroid collides with earth at relativistic speeds. At what speed will the asteroid cause the most damage?

>> No.9911365

If O2 has a higher molar mass than H2O, why do bubbles float in water?

>> No.9911370

>>9911365
because O2 has a lower density than H2O

>> No.9911449

>>9911365
H2O molecules are polar so they 'love' each other. O2 molecules aren't so they just go about their business.

>> No.9911453

I have a problem concerning the method of Lagrange Multipliers. I have a problem (of which I knew the solution) in which I wanted to maximize a function [math] f(x,y,z) [/math] under the constraint [math] g(x,y,z) = 0 [/math] (typical Lagrange Multipliers setup), but also under the constraint [math] 1 > x,y,z [/math].

I did Lagrange Multipliers and I got the expected answer. My question is just if I lucked out, or if this is actually valid?

>> No.9911538

Does freewill exists? It looks like all our thoughts are determined by external factors, events that dont depend on us, so how can you say you made a decision on your own?

>> No.9911553
File: 64 KB, 960x627, it&#039;s flaaaaaaaaaaaaaaat.jpg [View same] [iqdb] [saucenao] [google]
9911553

Thanks to jewtube algorithms I ended up watching some flat earth related videos and a fucker in the comments brought up an "argument" about the magnetic field or something. That got me thinking, wouldn't there be a point on both the north and south poles where the compass would "flip"? The north is now in the direction where you came from, which before was the south. Has this been tested or witnessed before?

>> No.9911570
File: 97 KB, 690x460, dnews_files_2014_06_earth_magn.jpg [View same] [iqdb] [saucenao] [google]
9911570

>>9911553
Were the earth's magnetic field perfectly symmetrical, yes, but it isn't.

>> No.9911609
File: 72 KB, 593x720, sqtsci.jpg [View same] [iqdb] [saucenao] [google]
9911609

>>9911570
Then how does it work? If I were to walk from point a to b facing always the same direction I would start facing the north and end facing the south no?

>> No.9911655

>>9911609
Your compass doesn't point to the "north pole", it points to where the magnetic field tells it to, and earth's magnetic field is a bit messy as you can see from the image I posted. You may be looking straight at the geometric north pole, but depending on your position the compass might point a bit to the sides, it might point backwards or it might just stop working altogether.

>> No.9911686

>>9911655
duly noted, thanks anon

>> No.9911919

>>9911609
Yes, there is such a point, called the north magnetic pole. If you held a compass and walked past it, the compass would quickly turn to the new direction and you'd be walking magnetic south.
However... the pole is not as defined as the axis of Earth's rotation. And, it drifts. You can take it from here on the wider Internet to research this.

>> No.9912020

is calculating the order of an element of a group the same regardless of the operation the group is defined under? like if you define the operation a#b=a+b=ab do you still take the lowest power of n such that a^n=e where e is the identity of the group, or is the process different

>> No.9912026

>>9912020
meant to write a#b=a+b-ab

>> No.9912118

>>9912020
>is calculating the order of an element of a group the same regardless of the operation the group is defined under?
Yes.

>> No.9912122

Would it be any more effective to spray my nose with oxymetazoline hydrochloride nasal spray before snorting a basic powder? The idea is that my nose will be more acidic and it will break shit down easier.

>> No.9912170

How does a computer know that a certain series of zeros and ones means something. And don't jump over the question by saying that the computer is programmed to know the meaning of a certain series of zeros and ones. My question is, how can wire and plastic and metals be built in such a way that the combination can be taught that a certain series of zeros and ones means something, such as that 0100101 representis the letter A.

>> No.9912204

>>9911453
if you don't post the question, how the fuck are we gonna know you fucking brainlet???

>> No.9912210

>>9912020
>i have two groups with two different structures. Are they isomorphic??
what do you think you fucking retard??

>> No.9912223

>>9912210
>>i have two groups with two different structures. Are they isomorphic??
Who are you quoting?

>> No.9912231

>>9912210
>ask stupid question in stupid question thread
>get called stupid
rats.....

>> No.9912374

>>9912020
>>9912223
>>9912231
>classification of finite simple groups??
>nah nigga, i have a classification of ALL finite groups

>> No.9912383

If anyone here is into cryptology or c#, I'm trying to decode this string:

ZXhjsZW5IHdvmssIGNvbm5vcg==

It appears to be in base64, but it gives me nothing. Japcode gives me "esc wo" and ASCII gives me "7".

>> No.9912419
File: 57 KB, 645x588, 1529839123885.jpg [View same] [iqdb] [saucenao] [google]
9912419

Is Operations Research a meme? Is it basically an engineering job? Don't get me wrong I have no issue with having an applied job I just don't want a career that I could have just gotten with an engineering degree. Is it basically just excel work?

>> No.9912431

>>9912383
>ZXhjsZW5IHdvmssIGNvbm5vcg==
that's just gibberish

>> No.9912461

Is it possible to build a matrix to convert lat/long to spherical xyz?
I mean i know the discrete formulas for each coordinate but i cant figure out how to put it into a matrix that I can start stacking against others. I have a reprojection formula i want to consolidate into as few matrices and operations as possible.

>> No.9912527

>>9912431
Could it be anything at all? It was a clue we found in a QR code, asked the guy who made the puzzle, he says it's correct.

>> No.9912555

>>9912419
what career do you want?

>> No.9912559

>>9912555
I have no idea. I'm strongly considering being a Quantitative (Research) Analyst but my question was about Operations Research Analysts.

>> No.9912563

>>9912461
> Is it possible to build a matrix to convert lat/long to spherical xyz?
No. The transformation isn't linear.

>> No.9912573

>>9912383
The string has length 27, but base64 has to be a multiple of 4. If you discard the first 3 bytes, you get
> \x8e\xc6V\xe4\x81\xdd\xbek, connor
where the \x?? are hex escapes.

>> No.9912582

>>9912573
The "Connor" makes sense! So maybe just got through and start discarding bytes? Maybe it'll make a message?

>> No.9912589 [DELETED] 

>>9912582
>>9912573
Okay, that's not really working.

>> No.9912596

>>9912573
>>9912582
Okay, that's not really working. All I've got is "exc wo" and "Vk, connor"

>> No.9912763

Looking for ways to stick to something
I just can't stick to something, even if my live and livelyhood depends on it

>> No.9912765

>>9902922
>>9902922
Brainlet here, is there a way to access patents for free/for the layman, or do you need some special license?

>> No.9912873

>>9912765
https://www.uspto.gov/patents-application-process/search-patents

>> No.9912994

>>9912559
>I have no idea.
How can you have no idea what career you want? How old are you?

>> No.9913018
File: 40 KB, 220x311, DAD75E0B-C688-4718-AC79-7E214637AB25.jpg [View same] [iqdb] [saucenao] [google]
9913018

>>9912913

Here’s a doozy

Basically the question is:

If we’re all made up up 50% of dna from our parents, is having sex with someone equivilent to having sex with basically their parents?

Is there actual physical difference in the cells/physiology of us and our parents or are we just half of each mashed together?

Pic related, how much of Johnny Depp is physically a part of Johnny Depps daughter who looks just like him?

>> No.9913098

>>9913018
Yes. You're also having sex with all their ancestry all the way to the first unicellular organism.

>> No.9913417

>>9912170
Do you know the "Chinese Room" Problem?
That's basically what a computer is. The CPU doesn't understand what it is doing. All it does is take instructions (letters to the man), read what instruction corresponds to what operation (read what symbol corresponds to what other symbol) and send outputs (return letters).
More powerful CPUs have (to follow the analogy) more rooms (multicore), more men (higher transistor counts), faster men (higher frequency), more detailed books (larger instruction sets) and more efficient books (improved instruction sets)

>> No.9913504

Are there any actual videos of the double slit experiment of quantum mechanics online? I can only find popsci animations on youtube

>> No.9913564
File: 117 KB, 1280x720, max78yg7h8yhresdefault.jpg [View same] [iqdb] [saucenao] [google]
9913564

What is the comfiest science (or math) degree?

Is it biomedical engineering?
>growing field, in demand, good jobs
>median $80k/ yr
>work in a lab/hospital setting without the yuckiness of a hospital
>low intensity curriculum, can pass undergrad on cruise control

why it isn't others:
>math: no jobs
>biology: forever unemployed
>physics: few jobs and dense content requires a lifetime of learning
>chemistry: dangerous, smelly chemicals, undergrad is 4 years of rote memorization
>medical: high stress, fast paced environment
>civil engineering: dirty and loud machinery
>mechanical engineering: civil engineering with car-bros
>aerospace engineering: highly competitive
>computer science: overcrowded, competitive, no careers only gigs


Other contenders: electrical engineering, chemical engineering, geology, statistics

What do you think?

>> No.9913933

>>9913504
https://www.youtube.com/watch?v=pVK67lNfgeE

>> No.9914988

>>9913933
I was hoping to see the physical apparatus as well but thanks anyway.

>> No.9915120

Lads, how the frick do you decide on a master's thesis topic?

>> No.9915236

Math brainlet here, pls halp
I have two numbers in an array, total female and total male population of a country.
How can I use them to calculate the "female to male ratio" of the country?

>> No.9915250
File: 215 KB, 1403x1403, 1532509990547-b.jpg [View same] [iqdb] [saucenao] [google]
9915250

Why is it that small butane torches produce a much hotter flame than the butane flame that comes out of an oven or stove top?

>> No.9915275

>>9915236
Divide the smaller total by the larger.

>> No.9915278

>>9915120
tell me what subject you're interested in and ill give you a topic

>> No.9915283

>>9903701
Lol I remember reading this exact question /fit/ here

>> No.9915316
File: 26 KB, 831x117, b59ba61678ba085f49f709b551e702a6.png [View same] [iqdb] [saucenao] [google]
9915316

Can anyone answer the second part of the question? If [math]\alpha[/math] is an infinite extension, the clearly it is an isomorphism [math]k(\alpha)\cong k(t)[/math] sending [math]\alpha[/math] to [math]t[/math]. So I have to assume that the extension is then finite to find some counterexample, but any element of [math]k(\alpha)[/math] is a rational expression with the top and bottom of the fraction being linear combinations of powers of [math]\alpha[/math]... how is it not going to be an onto function?

Maybe there is a typo and the question meant to have the arrow the other way around? Or they meant to say not injective?

>> No.9915892

>>9915236
wtf and I thought my question was dumb

>> No.9915944

What does the physics post-grad and post-doc scene look like right now? Still miserable?

I'd really like to spend the rest of my life researching and studying physics but not if I can't make an earnest living doing it.

>> No.9916680

>>9915278
mechanical engineering

i want to work in automation

>> No.9916687

>>9913564
>chemistry: dangerous, smelly chemicals
crybaby

>> No.9916688

>>9916680
hmm... algebraic k-theory is a good start

>> No.9916697

>>9916688
thanks for the unhelpful response fag

>> No.9916700

>>9916697
pick your own subject, brainlet

>> No.9916741

>>9916697
>fag
Why the homophobia?

>> No.9916785

Does QM explain the philosophical problem of Being and becoming? Are all points in spacetime eternally fixed and we are just part of a wave emanating through this substrate we call the universe?

>> No.9916943

>>9916785
No... This is what we call the "Quantum Woo" effect.

Try not to read too much into QM. I mean, it's weird, yes, but it isn't magic. It's just that your mind didn't evolve having to deal with this nitty gritty level of physics, so everything in that world seems quite counter-intuitive and thus "magical". QM doesn't answer any philosophical, religious, or spiritual questions, unless you bend over backwards to make it do so - which a lot of people make careers out of, adding to the misplaced mysticism.

>> No.9917045

>>9904254
It would require the same amount of energy, just less effort. The same way if a body builder pulls 200 lbs behind him it takes less effort than if I pulled it. The forces of gravity, friction and (negligible) air resistance is the exact same, but his effort is less but the energy is the same

>> No.9917419

>>9917045
>the body is perfectly efficient
>you cannot train the body to be more efficient
you are actually retarded

>> No.9917874

There is a lot to learn by heart when you study math, but how do you do it ? Do you just repeat the laws, properties and statements, walking in circles in your bedroom, just like you would study History for a test ?

>> No.9917945

>>9917874
Practice deriving stuff from the basic principles. There isn't much that needs to be learned by rote.

>> No.9917957

Can anyone tell me which universities are worth going to for a maths with computer science degree in the UK? I'm thinking of applying for oxford since cambridge doesn't offer the course but almost everyone I talk to says it's more for arts and humanities.

>> No.9918237
File: 28 KB, 591x716, 1526564312963.jpg [View same] [iqdb] [saucenao] [google]
9918237

Hey, /sci/. I want to learn math and science. I have a very(VERY) fragmented knowledge on these two subjects. Some matrix stuff, some vector stuff, some highschool level algebra, some euclidean geometry, some newtonian stuff, some optics and so on. I can't emphasize enough on how fragmented this is. Which means that I can't really do much with what I have. I want to get on a level where I understand math, science and problem solving enough to prove things by myself, make my own systems, write my own renderer, etc. Basically be able to reinvent the wheels so I can fully understand what I'm doing.
So, my question is-- is there any good book, or a list of good books with a "path" that will take me from middle school level to advanced math and science?
I've tried KhanAcademy but I find the explanations rather long winded and time consuming, I'd rather understand the concepts fast and start solving practice problems right away(MathIsFun helps but I have no idea what I should be learning or in what order things should be learnt).
Thanks

>> No.9918274

>>9917957
If I was British, I'd go to Nottingham.

>> No.9918280

Assuming that humanity didn't become extinct because of some natural disaster, nuclear bombs or the like, do you think that it would be possible to know all that there is to know?

>> No.9918285

idk if this is good place to ask but:

>egg yolks macros for 100g
>carbohydrates :3.6g
>of which sugars 0.6g
>of which fiber: 0g

WHATS THE MISSING 3G
Ive found something about substance called squalene and it peeked my curiosity.

Not to mention, egg yolks are amazing nutrition wise.

>> No.9918359

>>9918237
1: Start here https://www.docdroid.net/K1VENuF/basic-mathematics-serge-lang.pdf

This will give you the basics, you will not get a good understanding but it's what you need to get to the good books, try to focus on your intuition, for stuff like analysis or algebra try to give geometrical interpretations to it, seeing numbers as squares or the area of squares helps. It doesn't needs to be perfect, just to give you some intuition.

2: "Book of Proof" By Hammack, the online version is free, this will help you start to get what math is all about, this is a math book so read carefully and make sure you understand every word, learning math is hard and takes a long time.

3: "A mathematical Introduction to Logic" by Enderton, it will teach you logic and set theory, both important subjects, pay a lot of attention so you can abstract what "mathematical structure" and "mathematical theory" mean.

4: "Mathematics, form and structure" By Mac Lane, this is an introduction to all the other areas, read the first two chapters and then choose what you want to study, if you want to learn analysis/calculus then read the chapter as an introduction and check the wiki for a good book on it, apply the same reasoning to all the areas of the book and by the time you finished you will know as much as a decent math major.

Best of luck.

>> No.9918375

>>9917945
yeah, until defining an object takes 1 page

>> No.9918377

>>9917957
oxford is top in pure math, forget brainlets. Your best bet would probably be Warwick

>> No.9918378

>>9918285
probably some long molecules like amylose and amylopectin or something

>> No.9918404
File: 613 KB, 3270x3381, sisyphus.png [View same] [iqdb] [saucenao] [google]
9918404

>>9902922
Can someone please explain to me MSc of research and PhD ?

how do you study? and I hear that you need to publish somthing

please someone explain to me how all of this works, i'll appreciate it

>> No.9918466

>>9918377
>>9918274
Why do you say those? I have to say I never really considered either of them. From what I've seen warwick focusses more on software engineering. Is imperial college London good? What about bath or Durham?

>> No.9918486

>>9918466
Imperial and bath are also top tier, but living etc is pretty expensive (more so in london obviously). I studied in Durham and it's good for math (which is what i studied) but not great for CS, so i wouldnt know what to say. I also know about warwick cos im studying my phd there, but again it's for math not for CS so i cant know too much

>> No.9918488

>>9902970
>hello internet predict my future! is it going to be good I need the validation to function as a human being

>> No.9918515

>>9902922
I have some sort of bullshit learning disability that prevents me from holding numbers in my head while doing even the simplest of math problems.

I've always been terrible at math, but I never understood the root of my problem until lately. It isn't the procedures that I need to perform in order to complete the problem, but it really is my fucking memory.

Like I just attempted 3 + (3 * (7 + 19.5))) and I kept winding up with 52.9, but it was only until I realized that I for some fucking reason was applying the multiplication of 3 to 19.5 instead of 26.5, even though I did the addition of 19.5 + 7 in my head and arrived at 26.5..

Are there any specific ways for me to broaden my memory whenever it comes to storing numbers while doing mental math? Is the answer just to do math problems every day and continuously fail until I get better?

>> No.9918524

>>9918515
yeah... just use a calculator or pen/paper?? literally no use for mental math other than very trivial calcs in day to day life

>> No.9918526

>>9918359
Thank you. I'll be reading the books and go along the way you mentioned. The PDF you linked is what I was looking for to start out in math. Perfect. Thanks again.

>> No.9918586
File: 32 KB, 300x100, 79.png [View same] [iqdb] [saucenao] [google]
9918586

Question for Americans: What is meant by "college algebra" in your institutions?

I keep reading that it is required to graduate for the majority of degrees and there are many whiners who detest this. In Canada, most degrees require introductory linear algebra and single variable calculus classes. Most diploma and certificates also require their own specialized math classes. There are few people who are unhappy with this, but they either drop out of just carry on. But there are zero classes named "college algebra". The only precalculus you will find in a Canadian institiution is in the form of high school equivalency (grades 10 through 12).

The only traces of a cirriculum I can find indicate that it is mostly what would be considered elementary algebra plus a touch of linear algebra.

So, what is this college algebra? And why is it so hated? Pic unrelated

>> No.9918657

>>9918515
Same here but i'm in theoretical physics, just use pen and paper. If you ever find a solution for this mental fog please tell me.

>> No.9918683
File: 394 KB, 860x5600, a look at the serious courses in college today.png [View same] [iqdb] [saucenao] [google]
9918683

>>9918586
college algebra is middle school algebra, believe it or not. Pic very related

>> No.9919020
File: 132 KB, 1500x1500, 24oz.jpg [View same] [iqdb] [saucenao] [google]
9919020

>>9902922
hi. it's been 20 years since geometry class and i can't deal with relearning it all right now.

but i have a problem and i know it's a long shot to get any actual help on the chans, but i thought it'd be best to ask someone who has this knowledge at the forefront of their minds (like you might ask your mom a recipe)

anyway, there's a disposable bowl i am looking at buying in bulk (300) for portion control to lose weight.

it claims to be 24oz, but i am having a hard time picturing what dimensions (depth and avg. diameter) it may have, to see if it is suitable to hold a full meal (8oz boiled chicken breast, 8 oz steamed broccoli, and maybe 8oz of steamed rice)

i'm sure there's a formula i used to know. and some conversion table for cubic inches to fluid ounces.

it's just 20 years buried.

please help. thanks.

>> No.9919106

>>9919020
volume and weight are two entirely different things, however they are often muddled together because there is a density relation between them.

When a bowl claims to be 24 oz, it means it can hold 24 oz of water, which has a constant and uniform density. So you can look up google for the density of water (im european so i measure density in kg/m^3 and i know water is 1000kg/m^3 but idk the american one), and knowing that, you can calculate the exact volume of the bowl. However, a bowl has 2 degrees of freedom in dimension: it has both depth and diameter, so it is impossible to calculate what the depth and diameter are at the same time from just a volume calculation.

But now you claim you have 8oz of food... those are weight measurements and they all have variable density, which is much higher than water. In particular, they will occupy much more space for the same weight of water. Therefore i can tell you this much 24oz of food will NOT fit in a 24 oz bowl by a LARGE margin.

>> No.9919129

How can I learn precalc and geometry in a week. I already know trig.

>> No.9919130

>>9919106
>But now you claim you have 8oz of food... those are weight measurements and they all have variable density, which is much higher than water. In particular, they will occupy much more space for the same weight of water. Therefore i can tell you this much 24oz of food will NOT fit in a 24 oz bowl by a LARGE margin.
right. that was just an aside. weight oz =/= fluid oz. just saying i need my meal which is that description to fit in whatever bowl i buy.

given the pic provided, estimating the pixel count of depth * diameter (accounting for angle of shot)

let's go with metric, that's fine too.
24oz = ~0.7 liters

>> No.9919159

>>9919130
Can you call up the company who you are looking into purchasing the bowls from and ask them the depth and diameter of the bowls? If not, then can you access them in person and measure one with measuring tape?

You say average diameter. So are you purchasing three hundred bowls of different diameters?

Why do you need 300 bowls if you only need them for portioning out your food?

>> No.9919165

>>9919159
it's on amazon. can't find a number to call.
no store to walk into with a ruler.
avg diameter: top of bowls are a bit wider than the bottom of bowls. needs avg to find exact volume.

>> No.9919184

ok, so i counted pixels.

the depth:diameter ratio seems to be about 1:4.4
now if that volume is equal to 0.7 liter, what it the diameter?

>> No.9919266

>>9918683
That is somewhat terrifying. Innumeracy isn't a meme after all...

>> No.9919283

>>9919184
[eqn] D=3.8063 \times \sqrt[3]{x} \quad \textrm{where} \quad x=\frac{D}{H} [/eqn]
this is in inches assuming the conversion 24 fl oz = 43.31 cubic inches and in case it doesn't come out completely clear that is the cube root of x

given x to be 4.4 I got D to be 6.24 inches, but I have a hard time believing that the ratio is much greater than 3:1

to me it seems like you just need to figure out what the volume of the meal you are making is, perhaps pre cook it and try to determine it's volume with another container, if the volume of the meal is less than that of the container it should fit regardless of what the diameter is

>> No.9919670

>>9918280
Possible to collectively know all that is knowable, maybe.

https://www.youtube.com/watch?v=ojEq-tTjcc0

>> No.9919682

>>9902970
Success in education and success in the world at large tend to correlate, though not directly, and only because they tend to involve the same skill sets.

When it comes to top percentiles of income, a greater predictor is how rich and connected your family was to start with (class mobility happens, but it is the exception to the rule), though top percentile students rarely perform badly when it comes to income.

>> No.9919788

>>9918404
Bump this question

>> No.9919793
File: 32 KB, 480x360, D3465A26-816E-4521-B9BF-BCB33E4930B6.jpg [View same] [iqdb] [saucenao] [google]
9919793

MATH HELP
Not looking for tutoring or homework help, but actually just need some help doing a specific piece of math for some personal research.
I apologise for the sort of /pol/ focus, though I’m not trying to make any sort of statement through posting this, I just need some help with the numbers.

Basically, this is what I’ve got:

>Supposed Wage Gap:
>Women $0.79 -- Men $1.00

Hours worked:
Women 7.8 -- Men 8.2

“Prime” Wage Premium (Individuals who are in their prime):
Women 8% -- Men 0% (N/A)

Work Force Ratio:
Women 46.8% -- Men 53.2%

18+ General Population Ratio:
Women 51% -- Men 49%

Actual Pay Difference Ratio in Same Fields w/ Same Experience:
Women 0% (N/A) -- Men 4%

>Actual Wage Gap:
>Women $ -- Men $

What I need help with is calculating that final actual wage gap. This research isn’t going to be used towards anything beyond a note on my computer. I’ve got an original number, and factors that change the number. I just don’t know how to get the final number.

>t. retard that doesn’t know basic math

>> No.9919834

>>9919793
I assume this is for some incel debate... Thing is, statistics like these miss a lot of factors - such as the fact that men are more apt to take dangerous jobs (which would no doubt boost your case). Ya can't just take "all working women and all working men and all jobs", and have a statistic that really means anything. Plus these numbers will vary wildly with what source you use, and with how you break them down.

"There's lies, damn lies, and statistics" is a saying for a reason.

In any case, even for your flawed purpose, most of those numbers are irrelevant. The last one and the wage is all you need, though ultimately, even if the math is right, the answer would still be wrong.

>> No.9920041

Where do I start if I want to re-learn math before attending university?

>> No.9920060

>>9919793
For a proper wage gap argument, you need to compare hourly wage (never monthly/annual wage) for equal occupations with equal levels of qualification, experience and productivity (which is hard to measure, as it also includes factors like sickness, holidays and personal effort/motivation). Nobody does this, because most of the people researching wage gap are trying to prove it exists.

>> No.9920063

>>9920041
Khan Academy

Many universities also offer a maths primer and rehash course a few weeks in advance of regular classes. The expected learning speed is rather breakneck, so don't despair if you struggle for a bit.

>> No.9920277

>>9912170
Some basic set of instructions is wired into the hardware (which mainly consists of electronically triggered switches).

>> No.9920281

>>9913018
Here's a doozy. Incest happens to a degree in your ancestry. There would not be enough people on earth otherwise.

>> No.9920375
File: 6 KB, 208x249, 1519874503745s.jpg [View same] [iqdb] [saucenao] [google]
9920375

Any maths major here get BTFO by the epic compendium 'God Created the integers'. -edited by the late Stephen Hawking

I struggled, really struggled - it showed me I know nothing!
It's scary that we have somehow gleaned this knowledge.
It makes me want to lock myself in a room for a very long time to understand everything.

I dont think I can understand the total significance of the book, in one life time.
This makes me very sad.
How did these men come reach these levels of understanding in such brutish and technologically primitive times?

Euclid
>he aint so tuff.

Archimedes
> no biggie

Diophantus
> ok

Newton
>warming up sweating

Euler
> putting the effort in

Laplace, Fournier, Gass, Riemann, Cauchy.
>ok, slow the f' down! Let me go over this!


Cantor, Boole, Turing, DedKind, Godel
>yeah yeah, I know what they did they can wait... I've no hope.

>> No.9920383

>>9920333
shit i should have put my thread in here

>> No.9920434
File: 42 KB, 712x712, 1445807945596.jpg [View same] [iqdb] [saucenao] [google]
9920434

Why are abstract concepts hard to understand?

>> No.9920457

>>9920383
Seems ya already had it answered. It's not enough simply to move faster that orbital velocity - there's a reason rockets point up, and aren't on circular tracks.

Dunno about the ufospiracy thing the other guy posted there, but it seems if the charged superfluid in a torus thing worked, someone woulda at least put it up on youtube by now.

>>9920434
Abstract reasoning is the highest level of human intellectual capacity, and the only one that isn't possible without language. It isn't really natural, so much as it's learned - young kids and langageless adults can't do it, and those that learn language late in life have great difficulty with it.

>> No.9920788

>>9902922
Does friction 'violate' the conservation of momentum? It should based on energy analysis, right?
Basically, I just need someone to confirm that excess/unwanted angular momentum can indeed be dissipated as heat.

>> No.9920800

>>9920457
anon... I'm having trouble understanding the concept of an abstract concept. Can you describe it in terms of spatial logic?

>> No.9920873

"Use a double integral (polar coordinates) to determine the volume of the solid that is inside both the cylinder x^2+y^2=9 and the sphere x^2+y^2+z^2=16."

That's a problem from Paul's notes. The region of integration D is given by the equation x^2+y^2=3^2. I understood that, but I'm having trouble to mathematically mount the double integral to solve.

I thought it would be 2 integrals to calculate the volume, one for the cylinder and other one for the small slice of the sphere on top of the cylinder. Is this correct? Also, how do I mount the function to integrate these volumes?

Sorry for no latex

>> No.9920885

>>9920788
Friction in essence stretches the particles at the top of the surface. The only thing is that they are 'fixed' in place so the stretching manifests itself as the elastic energy of the surface, which in turn makes the molecules move and hence create heat.

>> No.9920944

>>9920873
start with volume [math]V = \int_D dV[/math]. I don't know exactly how you're meant to solve it or what tools you're given, but what I'd do:
>calculate the volume [math]V_{\text{cylinder}}[/math] of the cylinder up to the intersection of the sphere (you don't even need to integrate here really)
>compute the angle that the z-axis makes with a line from the origin to any point in the intersection, call this angle [math]\xi[/math]
>compute the volume of the 'rounded-base cone' by integrating the sphere using the previous angle
>The integral should look like [math]V_{\text{rbc}}=\int_D dV=\int _0^{2\pi}\int_0^4 \int_0^\xi r^2\sin\theta \;d\theta dr d\phi[/math]
>Compute the volume of the cone whose base is the cylinder, and take this off [math]V_{\text{rbc}}[/math]
>multiply the latter result by 2 and then add it [math]V_{\text{cylinder}}[/math]

>> No.9921076

>>9920944
Thanks, but a lot of these techniques you used I still have to learn

>> No.9921213

>>9921076
wut? I literally used the polar integral the question wanted you to use, the rest is really basic shit, what are you on about?

Do you not know how to calculate the volume of a cylinder? Do you not know how to calculate the angle between two lines? Do you not know how to calculate the volume of a cylinder? If you don't know how to do any of these, then why are you doing calculus¿

>> No.9921337
File: 763 KB, 1024x768, Koala.jpg [View same] [iqdb] [saucenao] [google]
9921337

Recommend me scientific YouTube videos and channels. I also love archaeology videos. Thank you!!

>> No.9921363

>> No.9920788
> Does friction 'violate' the conservation of momentum?
No; see Newton's third law.

Friction results in equal and opposite forces, so any momentum lost by one object is gained by the other.

However, as it reduces the difference between the velocities, it will always result in a net loss of kinetic energy from any reference point.

>> No.9921368

>>9920788
>>9921363

>> No.9921440

>ask all your brainlet questions that definitely don't deserve their own thread

There are complex, highly non-linear systems, which are "fault-tolerant" in equilibrium state (human body, ecosystems, universe as a whole, global trade, etc.). Is there a theory about such type of systems or do you know any resources? What is known about them?

>> No.9921461

>>9921337
One of the few guys who use computerized voices that I actually like
https://www.youtube.com/channel/UC7BhHN8NyMMru2RUygnDXSg/videos

>> No.9921462

>>9921337
Is this a question?

>> No.9921472
File: 1.23 MB, 3216x2461, 1533481080692.jpg [View same] [iqdb] [saucenao] [google]
9921472

can someone pls help me say bad things about this chat?
me am dumb and not know good counter argument ;_;

can you find any r ?

>> No.9921475

>>9919165
There's a questions section for listings, and the seller will probably chirp back at your questions.

>> No.9921478

>>9921472
go back to /smg/, knees
you also have to give more than this. the axis don't mean much without explanation

>> No.9921526
File: 526 KB, 364x489, sweatysnaek.gif [View same] [iqdb] [saucenao] [google]
9921526

>>9921478
this no Knees, haha who am that O.O;

am not knowing much more about this chart than you
was hoping someone knew how to read it here
this whole chart probably made up fud, amint it? X.X

>> No.9921534

>>9921526
without a citation it may as well be made up, yes
even if we assume the data presented is real, I cant evaluate what it means without understanding what the axis mean
there's simply not enough information in the chart to draw a conclusion

>> No.9922232
File: 155 KB, 840x573, filesize&amp;colon;155.35_KB &#039;modified&#039;&amp;colon;12&amp;sol;20&amp;sol;2017 date_tags_are_mdy 6u87K.jpg [View same] [iqdb] [saucenao] [google]
9922232

A student told me that the blood in your penis will turns into jelly after having an erection for a long time. (Maybe by "jelly" he meant that it becomes more viscous.) Is there any truth to that claim?

pic unrelated

>> No.9922290

Is humanity doomed?

>> No.9922349

>>9922232
no, i think he got it confused with that snake bite which turns your blood into jelly and can result in priapism, there was a youtube video of it somewhere, a doctor draining a jelly blood dick

>> No.9922619

RPGfag here. I'm illiterate in chemistry. Is it possible to combine obsidian and diamond to make a sharper and stronger material?

>> No.9922827

>>9920375
simple, they were just ahead of their time anon. sometimes you just have to accept that their brains were matured far ahead and these are only the few who have survived.

there were many scientists who were killed for having too much knowledge than the normal person. it was only recently that people with high IQ were getting positive treatment.

i still wonder how egyptians and indians got the exact distances to sun and moon with a difference of 100s of thousands which is not a big difference considering we didnt have exact metrics.
how the mayans calculated the calendars.
i think sometimes it has to do with collective knowledge.
if you think about it, most of these scientists were working with atleast one more person where they bounced off ideas. doing these alone is legendary but to counter genius people had to team up and force the genius.
but that grouping up led to diluting the genius midway somewhere.
as you can see my thought process on this is still not coherent and im still learning as life is moving forward. ive just begun to accept that they are ahead of time and no matter what you cannot make up that time in terms of experience at all.

Peace.

>> No.9922884

>>9922619
You can, technically, forge obsidian, and while I suppose you could make add a diamond edge, you can't forge diamond with the tech available in most RPGs. Adding diamond dust to your obsidian would likely do more harm than good.

https://www.youtube.com/watch?v=CA3lIuN_zVE

But, if your setting has magic, surely the "fundamental properties of diamond" could be used to somehow enhance the obsidian.

>> No.9922937
File: 193 KB, 1682x844, sqt.jpg [View same] [iqdb] [saucenao] [google]
9922937

An enchantment can be put on one of 7 elements (Head Chest Hands etc). I need to puzzle enchantments with items. I can put 2 enchantments on one item. So I can have max of 14 enchantments on 7 items. I only need to fit in 9 enchantments from the list. How do i go about it?http://elderscrolls.wikia.com/wiki/Enchanting_(Skyrim)#Apparel

>> No.9922956
File: 161 KB, 1920x1080, Untitled.jpg [View same] [iqdb] [saucenao] [google]
9922956

>>9922937
This just came up but i still want to know the method to solve this because it might come in handy later.

>> No.9923007

>>9922937
>>9922956
Standard backtracking algorithm.

1. Make your a choice among all possible choices (which you do not remember as impossible), save it on a stack
2. Add all choices that follow from that
3. If no contradiction arises, go back to 1.
4. If there is a contradiction, remember the current configuration (all choices on the stack) as impossible, and pop choices from the stack until you are out of the "impossible" area

If you have a big problem of this kind, you can try to formulate it as SAT-problem and give it to a SAT-solver, but that is probably out of scope for you

>> No.9923024

>>9922290
That depends. Do you believe in religion or science?

>>9922349
I think that you are being duplicitous.

>> No.9923143

>>9923024
i wasn't 100% correct and there are no dicks in the video just the doctor saying what he'd do but it's this video https://www.youtube.com/watch?v=JN0VtHez9xI

>> No.9923181

how do I prove a 3x3 magic square with sum 15 and unique entries {1,2,...,9}??
I tried saying that you can just make all the entries 5 then modify them with a variable k as an equality (doing the inverse operation on the other side, skipping the middle). But I see this works only for some k

>> No.9923382

>>9922827
>i still wonder how egyptians and indians got the exact distances to sun and moon with a difference of 100s of
Trigonometry?

>> No.9923454
File: 36 KB, 795x244, Capture.png [View same] [iqdb] [saucenao] [google]
9923454

How do I prove this?
It makes sense, why each factor is where it is, but I don't know how to derive this.

>> No.9923528

>>9923454
Lorentz force and the definition of curvature, you literally just combine them and out pops this equation

>> No.9923561

>>9923528
I have no idea what you mean by the definition of curvature, in the context that it is something you can combine with the Lorentz foce.

>> No.9923646

>>9923561
[eqn] \frac{1}{r} = \kappa = \left \| \frac{d T}{ds} \right \| = \frac{\left \| \frac{d T}{dt} \right \|}{\left \| \frac{d \vec{s}}{dt} \right \|} \\\
\left \| \frac{d T}{dt} \right \| = \frac{\left \| \frac{d^2 \vec{s}}{dt^2} \right \|}{\left \| \frac{d \vec{s}}{dt} \right \|} \\\
\left \| \frac{d^2 \vec{s}}{dt^2} \right \| = a=\frac{F}{m} = \frac{qvB}{m} \\\
\left \| \frac{d \vec{s}}{dt} \right \| = v [/eqn]

you could also probably just use the formula for centripetal acceleration since they didn't ask you to prove that the path is a circle, but that's "circular reasoning" if you ask me, this method at least gives a good basis for proving that the path truly is a circle.

>> No.9923661

>>9923646
Whatever you said, it isn't parsing correctly.

>> No.9923663

>>9923661
turn off adblock you simp

>> No.9923669

>>9923646
It's a level 1 university course, I have no idea what logic you were following there and I'm sure a simple solution is fine.
Also, it's a given that there's centripetal acceleration, since it's perpendicular to motion, and that should always create a circle if the electron motion is perpendicular to the magnetic field.

>>9923663
>adblock blocks MathJax
why tho

>> No.9923772
File: 11 KB, 249x249, 1532746289340.jpg [View same] [iqdb] [saucenao] [google]
9923772

I keep ending up in situations where I need to tell people that the approximated probability for doing a given action in a set amount of attempts is 1-(1-P)^n, and I've been corrected about it almost every time. Surely I'm the retard here, so I need help on figuring out the actual equation.

>> No.9924079
File: 5 KB, 409x56, 0179618b3b13cdd45bb73a39050a2b58.png [View same] [iqdb] [saucenao] [google]
9924079

Is anyone here familiar with MuPAD?

ive been trying to integrate some gross function but in the answer its giving me there is a sin^2 with no argument, what does this mean?

>> No.9924086

>>9924079
Taking a sine of x, would be sin(x). x is the argument taken by the function sin().

Sin^2() means the same as [sin()]^2. You still need an argument for the function, that is, an 'x', that you take the sin^2 from.

>> No.9924088

>>9924086
Sorry, I read your problem wrong, I was being retarded. Forget!

>> No.9924113

>>9924079
I'm not familiar with mupad, but I suspect that it wants sin(t)^2 rather than sin^2(t).

That's how maxima behaves; it uses sin^2 etc when displaying expressions but doesn't recognise that syntax for input.

>> No.9924120

>>9924113
yeah that fixed it, thanks bud

>> No.9924160

>>9923181
The rule that all rows, columns and diagonals sum to 15 gives you 8 equations in 9 unknowns. One of those is redundant, so you have 7 independent equations in 9 unknowns. Solving those gives you a solution family with 2 free variables. Then you can just use trial and error to find a solution where the 9 entries are distinct integers between 1 and 9 inclusive.

Solving the equations gives you
[ 10-u u-v+5 v]
[u+v-5 5 15-u-v]
[ 10-v v-u+5 u]

Given that the entries must be between 1 and 9, the 4 corners show that 1<=u,v<=9, the 4 edges show that 6<=u+v<=14, -4<=u-v<=4. The solution set is symmetric about u<=>10-u, v<=>10-v and <u,v><=><v,u>, so there's at least one solution with u<=5, v<=5, u<v, which narrows it down to 6 cases: (1,5),(2,4),(2,5),(3,4),(3,5),(4,5). Of those, (2,4) and (3,4) produce valid solutions, the other 4 contain duplicates (they're all [[8,2,5],[2,5,8],[5,8,2]]).

>> No.9924177

>>9923454
For the electron to move in a circle, you need the centripetal force to be equal to the magnetic force

F=ma=mv^2/r
F=qvB

qvB=mv^2/r

r=mv/qB

>> No.9924188

Recently inherited a light microscope, anyone has a guide for dummies how to use it?

>> No.9924191

>>9924188
https://prezi.com/5ome0j0stxpr/light-microscopes-for-dummies/

>> No.9924228
File: 14 KB, 568x194, 60e923da6c3b18c68115adde8bd7b4fc.png [View same] [iqdb] [saucenao] [google]
9924228

i think for this question im supposed to use spherical coordinates, and i have the equations for acceleration and velocity, but i dont how to to translate the information given to me into these equations, can anyone steer me right?

>> No.9924482
File: 69 KB, 1025x542, brain.jpg [View same] [iqdb] [saucenao] [google]
9924482

This is hurting my mathlet brain. This seems like it should be so easy, but I'm having a hard time wrapping my head around it.

>> No.9924507

>>9924482
What is the area? On how many tiles do you have to spread it?

>> No.9924566

>>9924482
Note that purposely one length is the double of the other.

>> No.9924587

>>9924482
Is it supposed to be squares? If so its impossible since we will need twice the amount of squares in the height direction as the width. This gives us that we need 2x * x = 2542 giving us x = sqrt(1271) which isnt an integer.

>> No.9924763
File: 73 KB, 1006x306, nani.png [View same] [iqdb] [saucenao] [google]
9924763

I am brainlet plz help

>> No.9924767

>>9924191
Thanks anon smooch

>> No.9924981

>>9924482
>>9924587
Assuming it's not square squares:
Width would be 8192 / 2542 = ~3.22
Height being double that @ ~6.44

If it is square squares, average that: ~4.83

Or just 0.0001, as it's just a matter of "fit them all in" - doesn't say it has to cover it all.

>> No.9925024
File: 133 KB, 652x611, Selection_016.png [View same] [iqdb] [saucenao] [google]
9925024

How do I do exercise 4 -- show that if S has n elements, (i) and (iii) are isomorphic.
Let K be either the field R of real numbers or the field C of complex numbers.

(i) set X of all row vectors: [math] (a_1,...,a_n), a_j \in K [\math]
(iii) set Y of all functions with values in K, defined on an arbitrary set S.

My interpretation of isomorphic: there exists some function, [math]\phi:X \rightarrow Y[/math] where X and Y are two linear spaces over the field K, and k an element of K, such that
(a) [math]\phi(X_1 + X_2) = \phi(X_1) + \phi(X_2)[\math] and
(b) [math]\phi(kX) = k\phi(X)[\math]

Here, would phi would be the function to take all the a_j's from X and map them into functions of a_j in Y. e.g., [math] \phi((a_1,...,a_n)) = \{f(a_j)\} [\math] ? If this was so, I don't think it'd be isomorphic.

>> No.9925041

I have a problem I'm interested in and the answer will effect how I design a program. Say you have a group of arbitrary size, and one group leader. The group leader has a file that he wants to share with all the group members, but the file is very large and he has limited bandwidth and time.

The most naive solution would be for the group leader to send the file to every member individually, but for a group of size (N) = 20, this would take time (t) = 20 and bandwidth (b) = 20. A slightly better solution would be for the group leader to send the file to member 1, 1 to 2, etc. This would make it so the bandwidth used by the group leader and all the members was only 1b, but t would still equal 20.

If the leader wasn't an idiot he could split the file into 20 chunks, give one to every member in t = 1, and then have every member rotate their chunks from 1 to 2, 2 to 3, and then back around from 20 to 1. This would take only t = 2 to complete, and every member except the group leader (who must necessarily use b = 1) would use only b = (N - 1) / N, but this is not the ideal solution, and I can demonstrate with a counterexample if you don't believe me.

My question is, what is the ideal solution for minimizing the time and bandwidth of an arbitrarily sized group?

>> No.9925046

>>9925024
oops, i used wrong slashes. hope this works

Let K be either the field R of real numbers or the field C of complex numbers.

(i) set X of all row vectors: (a1,...,an),aj∈K[/math]
(iii) set Y of all functions with values in K, defined on an arbitrary set S.

My interpretation of isomorphic: there exists some function,[math]\phi:X \rightarrow Y[/math] where X and Y are two linear spaces over the field K, and k an element of K, such that
(a) [math]\phi(X_1 + X_2) = \phi(X_1) + \phi(X_2)[/math] and
(b) [math]\phi(kX) = k\phi(X)[/math]

Here, would phi would be the function to take all the a_j's from X and map them into functions of a_j in Y. e.g., [math]\phi((a_1,...,a_n)) = \{f(a_j)\} [/math] ? If this was so, I don't think it'd be isomorphic.

>> No.9925190

>>9925024
you're thinking of this all wrong.
Define [math]Y:=\{f\;|\; f:S\to K\}[/math]. It is trivial to check that this is a linear space, so i'll leave it up to you.

Suppose [math]S=\{x_1,x_2,...,x_n\}[/math] has [math]n[/math] elements.
Define the linear map [math]\varphi: Y\to K^n[/math] by sending a function [math]f\mapsto (f(x_1),f(x_2),...,f(x_n))[/math]. It is trivially surjective, since for any point [math](a_1,...,a_n)\in K^n[/math], there exists a function [math]g[/math] mapping the [math]n[/math] elements of [math]S[/math] to those. It is also trivially injective, since any function is completely defined by the values it takes in [math]S[/math], and any two functions with the same image must coincide.

>> No.9925303

>>9925041
The total data transferred is N-1 times the file size. You can change how that's distributed amongst the group, but not the total.

With the "bucket brigade" approach, you can reduce latency (the time until all the last member has the complete file) by passing on each byte as soon as it's received, rather than waiting for the entire file to be received before starting to retransmit.

Minimising latency and sharing the workload equally are mutually exclusive. To minimise latency, the first person to receive a given byte needs to do more work than those who receive it later.

If each person only retransmits once, the last person to receive it will see N-1 hops of latency. Minimum latency is achieved by having everyone transmit continuously until everyone has the complete file, but this means that whoever receives the first byte does more work than those later in the queue.

>> No.9925628

>>9924160
Yeh this is pretty much what Strang did but I didn't wanna copy it. Thanks holmi

>> No.9925796
File: 72 KB, 317x286, edfd.png [View same] [iqdb] [saucenao] [google]
9925796

Anyone know of a good course on mechanics, more specifically body diagrams, all I can find on youtube are countless vids just explaining the concept in its most basic form.

So I'm looking for something that explains the concept from the most examples and progresses towards the more difficult ones.

>pic related of a guy just straight jumping into solving a body diagram without previously introducing... anything basically.

>> No.9925817

>>9903701
yea its all relative. picking up a dinner plate for you may be like picking up a 50 lbs plate for the other guy.

>> No.9925821

>>9925796
Dude, it's just vector addition.

If something isn't moving then the sum of forces equals zero.

The forces in the x-direction should equal zero. The forces in the y-direction should also equal zero.

>> No.9925836

>>9925821
ya I chose a bad example but I really need something explaining where to draw forces, like the forces go through the cables here. That makes sense, but I need more shit similar to that, like explaining support reactions etc.

>> No.9925844

>>9925836
>>9925796
https://ocw.mit.edu/courses/physics/8-01sc-classical-mechanics-fall-2016/index.htm

>> No.9925873

If photons move quantum particles then how come the universe isn't totally chaotic with no order? It just seems strange to me how things can go from totally random and chaotic to well structured. I mean when I shine light on my desk it doesn't bounce away but you are telling me the atoms that make up my desk will be bounced by light? That just seems insane to me but I am posting here because I am not a physicist.

>> No.9925879

>>9912170
Logic gates. I don't know how it physically works but logic gates will tell you all about how it "knows" things. Also you could look into a turing machine because that can model any computer.

>> No.9925898

>>9925873
Photons are quanta that transfer energy in the electromagnetic quantum field. If they didn't do this, the universe would be pure chaos and non-baryonic (basically, all dark matter). Additionally, it is massless particles, trapped in similar interactions, that create mass. Thus it's indeed these very interactions between quanta in these fields, and others, that gives rise to the illusion of order.

Popsci explanation:
https://www.youtube.com/watch?v=gSKzgpt4HBU

>> No.9926119
File: 85 KB, 804x802, 1532719411704.jpg [View same] [iqdb] [saucenao] [google]
9926119

>be me, absolutely hate (multi)linear algebra
>enrol in every course that doesn't have linear algebra requirements this semester in hope of avoiding it
>suddenly 2 weeks in linear algebra everywhere
>everything is vector space over finite fields in crypography course
>have to solve system of differential equations for DE course
>even combinatorics course needs me to solve eigenshit for graph matrices

How do I deal with this

>> No.9926208
File: 48 KB, 651x155, what.jpg [View same] [iqdb] [saucenao] [google]
9926208

Can somebody explain the answer to point d (pic related)? I understand the first part about multiplying by A inverse well enough. I don't quite get what the author is saying about the polynomials and how it leads to (B^2 + I) inverse having those eigenvalues.

I know I am retarded, but I want to make up for my botched linear algebra education somewhat.

>> No.9926228

>>9926119
drop out of math or nut up
trying to dodge linearity in math is like trying to dodge rain in a thunderstorm

>>9926208
Since [math]Bx = \lambda x, B^n x = \lamba^n x[/math]. This works for all powers, so if you act on x by a polynomial in B, it's just like multiplying x by a polynomial in lambda.
What the author is saying about the polynomial is the eigenvalues of p(B) are p(eigenvalues of B).
B^2+I is a polynomial in B.

>> No.9926239

>>9926228
>This works for all powers, so if you act on x by a polynomial in B, it's just like multiplying x by a polynomial in lambda.
This is the bit where I get lost. Multiplying x by a polynomial in lambda, does it mean making the same polynomial of lambda as I made of B? As in, lambda^2+1? I feel like I'm missing something crucial here, and I don't remember any of this crap being in high school math.

>> No.9926256

>>9926239
Yes, that's what it means.
For example, suppose your polynomial is [math]x^2+x+1[/math].

Then you'd do this: [math]p(B)x = (B^2+B+I)x = B^2 x + Bx +Ix = \lambda^2 x+\lambda x+x = (\lambda^2+\lambda+1)x = p(\lambda)x[/math].

It might be a bit confusing at first switching between p(B), which spits out a matrix, and p(\lambda), which spits out a number.

I would also say this is not high school math at the majority of American high schools.

>> No.9926276

>>9913018
Nature doesn't give a fuck about morals. We're all just the current generation trial run of an ancient ribozyme that got the bright idea to replicate. It's all been downhill from there.

If you replicate, your progenitors' (parents') genetic gamble worked. You pass on information with some mutations, and your DNA's body plan worked. If all of your children are sterile, or none of them survive to replicate, your genetic gamble is lost, and your genetic code is lost forever when you die (in a biological sense). The reason life prefers diverse body plans and genetic code is because it's evolutionarily viable to put your eggs in as many baskets as possible.

In short, any difference we assume exists between us as different humans, or between bananas, howler monkeys, viruses, and whales is fabrication. We're all products of the same successful descent and modification of an original replicating RNA precursor.

>> No.9926283

what is the main breakthrough in physics this year? and in 2k17?

>> No.9926311

>>9926256
Ok, thanks. I get it now. I guess I got confused by the notation.

>> No.9926378

>>9926283
>what is the main breakthrough in physics this year?
can't tell you until the end of the year
>and in 2k17?
https://www.drgoulu.com/wp-content/uploads/2017/09/Rheology-of-cats.pdf

>> No.9926459

>>9902922
Does electrostatic discharge affect human cells? When human cells are exposed to ionising radiation, the amount of electrons increases and the cells stop working, mutate or die. correct? This all happens because electrons get added to the cell's molecules and atoms so would a human's cells get damaged when receiving static charge?

>> No.9926474
File: 81 KB, 1300x866, 19246599-water-splash-with-bubbles-of-air-isolated-on-the-white-background.jpg [View same] [iqdb] [saucenao] [google]
9926474

What is the thin layer that forms between the water and the air called and what causes it?

>> No.9926478

>>9926474
Water surface? Surface Tension?

>> No.9926480
File: 81 KB, 719x458, solution-math-solid-geometry29-ans.png [View same] [iqdb] [saucenao] [google]
9926480

how can i estimate the total volume of a heap of granules including the air/water in between? i don't have physical access to them so i can't just pour them in a measuring cup.

going by the logic in pic related the heap could take up about 90% more volume than if you were to measure the displacement without the air in between? but that's presumably the worst case scenario since irl they wouldn't be perfectly stacked perfect spheres. what's a more reasonable estimate?

>> No.9926488

>>9926478
Oh shit I found it. It's called a meniscus.

>> No.9926506

>>9926480
a hcp of fcc will probably have larger densities
For a hcp-arrangement the packing factor is about [math]\frac{\pi}{3\sqrt{2}} \approx 74\%[/math]
For a fcc it's about 74%

>> No.9926564

>>9926506
ok i didn't know that this has been rigorously studied and what to google, tyvm anon
hcp or fcc would be the best case, and these would be more realistic figures in my scenario:
https://en.wikipedia.org/wiki/Random_close_pack

>> No.9926634

>>9925844
thank

>> No.9926635

>>9915250
Butane torches are conical, condenses butane into a smaller area, burns faster and hotter
Stove tops radiate flames outward, more area but less heat in that area

>> No.9926706

I have this integral that is bothering me. The probability density of a certain random vector [math]Y[/math] is computed as
[eqn] \pi_Y(y) = \int \delta(y-a-x)\pi_X(x)dx = \pi_X (y-a), [/eqn] where [math]y,x,a \in \mathbb{R}^n[/math] and [math]X[/math] is another random vector.
Now I know this is just abuse of notation and not a Riemann integral, but how should I briefly explain what it actually is? Is it correct to say that this is a Lebesgue integral where we are
using the Dirac delta as a measure? I haven't actually studied measure theory or Lebesgue integration besides what I learned by googling for half an hour. I'm only familiar with basic Riemann integration.
If it is a Lebesgue integral with delta as a measure, what would the steps look like if you did it properly? How would the 'argument shift' [math]a[/math] apply to the measure?

>> No.9926736 [DELETED] 

>>9926706
the formal definition of the dirac delta actually uses a limit definition of exponential functions. Hence using the standard theorems of lebesgue measure, you can conclude that it does make sense, but it has nothing to do with the measure

>> No.9926751

>>9926736
I just thought it might have something to do with the delta function as a measure since Wikipedia says the delta function can be understood as a measure with respect to which Lebesgue integration is performed. According to Wikipedia the delta function is a measure that gives the value 1 for sets that contain 0, and value 0 for all other sets.
Glad to know the integral makes sense though.

>> No.9926770

>>9926706
I'm a bit confused with regards to your notation.
That integral looks like a riemann integral to me (due to the [math]dx[/math]).
How is that [math]\delta[/math] defined?
If it were a dirac measure, one would conventionally notate such an integral as [math]\int \pi_X(x)d \delta_z(x)[/math], where [math]z \in \mathbb{R}^n[/math]. Such an integral would evaluate to [math]\pi_X(z)[/math] for instance.

>> No.9926779

>>9926770
I just read your post >>9926751.
I assume your delta refers to the dirac measure [math]\delta_0[/math], in which case your integral can be written as such: [math]\pi_Y(y) = \int \pi_X(x) d \delta_{y-a}(x)[/math] which does in fact evaluate to [math]\pi_X (y-a)[/math].

>> No.9926785

>>9926770
>>9926779
Thank you. Yes, the notation is strange but the book I got it from even admits it's just lazy notation and the integral should be handled as a Lebesgue integral or something, but the book doesn't go into any more detail.

>> No.9926868
File: 1 KB, 127x85, tfw70iq.png [View same] [iqdb] [saucenao] [google]
9926868

This question is so stupid it hurts me to ask it. I'm sure it won't take you long.

Can someone solve this indefinite integral for me and explain the reasoning behind it exactly? I may just be the most retarded person on earth when it comes to integrals. This shit makes me feel like a low functioning piece of rock but I just can't help it.

>> No.9926880

>>9926868
substitute z for e^x and then decompose the result into partial fractions.

>> No.9926889
File: 75 KB, 550x449, 1434542600721.jpg [View same] [iqdb] [saucenao] [google]
9926889

>>9926880
Fuck me sideways with a rotating sledgehammer, hadn't even considered it. Thanks man.

>> No.9926893

>>9926889
probably even better to subsitute z for e^x - 2 but both should work somehow

>> No.9927419

omg all your math tags are just plain text for me how do i fix it i'm using google chrome it used to work :S

>> No.9927495

>>9927419
>adblock

>> No.9927922

>>9902922
So i have one stupid question. How do you get the value of the interval on the x-axis. For example Im doing the simpsons, trapezoidal rule. So naturally you need to find the interval value that you will plug into your ((b-a/2n)(f(x0)+f(x1)..etc). you know how if you have the interval from x{0,2} when n=4 you have the interval 1/2,1,3/2,2. how do you formulate those number. Help

>> No.9928446

I have a pretty relatively decent understanding of Newtonian, classical and quantum mechanics - but i've never quite got quantum entanglement. It seems more like epistemology to me than a physical phenomenon - can someone explain? or better yet, tell me where I am going wrong?

Somehow in a system, say with 2 particles (an example would be nice?), they are interacting in a way where by if you observed one and determined it's velocity/spin/position - you know the state of the other particle due to invariance/conservation of information/symmetry.

Assuming you haven't determined this and these 2 particles seperate (example please?) - you could follow one particle outside of the others light cone, then at a future point check it's properties. By doing this you have determined the other particle's properties (which is outside the light cone of the other particle).

A couple of questions remain

1. This seems more like philosophy to me, much like the '2 people are in front of you - one will always lie, one will always tell the truth - find out which one is lying'.

2. What happens say, if the separated particle then collides with another particle, has an exchange and turns into another particle/anti particle? Then you couldn't determine the other particle? I'm not suggesting you've broken invariance, but particles hit each other and change all the time.

How badly have I got this wrong? Could anyone help please? I've looked up a few videos on youtube, read a few articles but it all seems to be tedx/lawrence 'your mind observing it changes it therefor quantum consciousness' kraus tier stuff.

>> No.9928578

>>9928446
>1. This seems more like philosophy to me, much like the '2 people are in front of you - one will always lie, one will always tell the truth - find out which one is lying'.
It's more that you made it so that they have (anti-)correlated spins. Like two electrons in an orbital having different spins: if you know the spin of one you know the spin of the other.
>2. What happens say, if the separated particle then collides with another particle, has an exchange and turns into another particle/anti particle?
Then you've broken entanglement. Once that happens you can't determine the corresponding state of the other particle by measuring your particle
>I'm not suggesting you've broken invariance, but particles hit each other and change all the time.
Which is why entanglement doesn't happen often. But in a controlled environment you can make it and keep it up for a long time