Stupid Question General #0

what course / books should i get for beginner math?

>>8952588
Zorich

>>8952602
meme book. couldn't understand from 2 page onwards

>>8952584
why are you trying to reformat everything into a cookie-cutter general format for literally no reason you fucking faggot
just use the regular sqt >>8949243

>>8953766

sqt failed everybody. It's not just that LITERALLY NOBODY ANSWERS ANYTHING MORE COMPLEX THAN FIRST 10 (MAYBE 11) GRADES EVER, it's that the lazy cunt who creates these threads sucks at his job. It was like a day straight with no sqt.

I'm not OP tho. We'll see how this thread goes.

>>8953766
You're confusing me with somebody.

>>8953752
honestly, khan academy.

>>8953876
> responds to meme with a bigger meme

>>8953878
Zorich is not a fucking meme retard.

Is the amount of matter infinite within an expanding universe?

What's the application of the Bachet weighing problem?

6 months in and still don't know.

>>8952588
This one:

http://www.matematica.net/portal/e-books/Graham - Knuth - Patashnik - Concrete Mathematics.pdf

It's a math book for CS guys, or as I say, math for brainlets.

>>8954022
If this link don't work, try this one:
http://www.matematica.net/portal/e-books/Graham%20-%20Knuth%20-%20Patashnik%20-%20%20Concrete%20Mathematics.pdf

>>8954013
No, the space between matter just increases.

>>8954026
If the space between matter increased we would all be dead.

>>8954013
The amount of matter has little to do with the expansion. It could be infinite or finite. Expansion just means that within any finite region, the density of space is decreasing.

>>8954032
> If the space between matter increased we would all be dead.
> The density of space is decreasing

Choose one, friendo.

Should I remind you that density is a quotient between mass and volume?

What books do you recommend for GRE preparation?

>>8954044
Density is the degree of compactness of something. The density of *matter* is between mass and volume. Space does not have mass, fool.

Expansion does not necessarily increase the space between matter because gravity keeps mass in the same galaxy together.

Since a wave-function may have uncertain energy, does that mean that quantum mechanics does not conserve energy?

>>8954054
>Since a wave-function may have uncertain energy, does that mean that quantum mechanics does not conserve energy

No energy is always conserved in QM, in interactions the sate collapses so CoE holds.

Why, again, do we mandate that a function can have only one output per input? Does it give rise to paradoxes? Is it just axiomatic?

>>8954177
>Why, again, do we mandate that a function can have only one output per input?
because it's useful

>Does it give rise to paradoxes?
no

> Is it just axiomatic?
it's a definition

>>8954180
>because it's useful
Could you expound on this point, please?

>>8954182
>Could you expound on this point, please?
functions show up in lots of places

like polynomials, exponentials, logarithms, etc.

>>8954182
Not OP but it allows for exactness when working e.g. knowing someone is taking the +ve square root where the negative would change the form of the answer. You can have many valued functions but they are typically restricted to a range in which they are injective (one to one) e.g. in complex numbers you can restrict a function to an arbitrary sheaf when moving from around the complex plane.

If you've not done complex numbdrs then you can also think of the inverse trig functions which are many valued but we restrict the range we consider them to make it clear what values are being taken

>>8954182
You can surely see how it is more useful to define, for example, [math]\sqrt{x}[/math] as only the positive root, instead of [math]\pm \sqrt{x}[/math], so that when I ask my function what the square root of 4 is, I get 1 unambiguous answer back instead of 2 to decide from

Would making a thread about a possible experiment that is sort of /x/ tier still be /sci/ related? I invented a thing called sensomancy and now I want to make sure it's safe. I have test subjects but they seem content to join my discord and say next to nothing or /x/ stuff. I sort of regret recruiting from /x/ and it probably wasn't a good idea for several reasons.

>>8954287
Well fuck it then. I'm just going to make the thread. Nevermind, what a waste of time and energy.

>>8954287
>>>/x/

>>8954367
It's too late. Would you be a willing test subject?

>>8952584

is that Japan?

>>8954381
Fag.

>>8954390
It's a legitimate experiment though. Plus I didn't wanna get banned.

Ok sci decide my grad school specialization between: applied electromagnetics/RF circuits, communications, optics/photonics, or signal+image processing/machine learning

Choose for me please i am too indecisive

is there a place that lists article titles from scientific journals?

>>8954411
Normally I'd pick a random option and add a persuasive argument to boot, despite being just a college dropout who's clearly incompetent, but I'll be nice this time.

Don't give away your power to choose. It's the only meaningful freedom you have, it's the only thing that makes life worthwhile.

Even by giving it away subtly by listening to other people's opinions you're setting yourself up. And you're doing directly.

EVERYBODY is an enemy. Don't add yourself to that list by asking others to decide for you.

What kind of math do I need to study to be able to git gud at 2D graphics programming drawing graphs with stuff like Cairo, Skia, etc?

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WTF?!

How the fuck can it possibly be 3 if IT'S BEHIND THE FUCKING MIRROR FFS (that's what sketchmarks are for isn't it?)?!

>>8956097
do you not know how mirrors work m8?

>>8956102
Well tell me cause to me this makes no fucking sense

Is it possible to make a function where phase changes in matter are omits output? Also is it possible for there to be infibite phasechanges with respect to internal energy?

A small problem I've been working on for a week, because I'm stupid. Please tell me if you see any flaws in my reasoning.

You have n points on a plane. If you take any 3 of these, they are not aligned ; also two straight lines joining different points are never parallels.

You join all points to one another with straight lines.

In how many points do the lines intersect, except for the n points you have at the beginning ? (we will note this number [math]N[/math])
A bit of space if you want to try it yourself. Since you're not as brainlet as me, you'll figure it out faster.

My reasoning :
For the first points you need to draw [math](n-1)[/math] lines, for the second, [math](n-2)[/math], and so on.

Total number of lines :
[eqn](n-1) + (n-2) + \dots + 1 = \sum\limits_{i=1}^{(n-1)} i = \frac{n(n-1)}{2}[/eqn]

Let's call this number [math]n'[/math].
Since none of the lines are parallel, you have [math]\binom{2}{n'}[/math] points in which the lines intersect.
Out of these points, you have the [math]n[/math] points you had at the beginning. These points account for more than one intersection. Indeed, in each of these points you have [math](n-1)[/math] lines, the point "going to" the other [math](n-1)[/math] points.

So each of those original points account for [math]\binom{2}{n-1}[math] intersection points. We can now conclude that :

[eqn]N = \binom{2}{n'} - n*\binom{2}{n-1}[eqn]

... where [math]n' = \frac{n(n-1)}{2}[/math].

The tests I've done with 3 (N=0), 4 (N=3), 5 (N=15) seems to work.
What do you think ?

>>8956166
I fucked up the TeX.
[math]\binom{2}{n-1}[/math] intersection points. We can now conclude that : [eqn]N = \binom{2}{n'} - n*\binom{2}{n-1}[/eqn] ... where [math]n' = \frac{n(n-1)}{2}[/math]

>>8956168
Well if we can conclude that, then what's the problem?

>>8956463
I was wondering if I did any mistake. Apparently you didn't spot one, so that's all good.

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How the fuck do we know what those angles in that small rectangle are equal to the left angle of the beige triangle? Makes no fucking sense.

>>8956509
nvm figured it out hahaha

>>8956097

PLS HELP

youre going to an all ages stem hall, what would you like to see?

brainstorming right now and Ive got:
>project classes (ham, robotics..)
>welding/workshops
>software/computer use
it's easy to engage the community for a community garden and hippie shit, but stem is a whole different thing

if you dont want to go in for a class, what would you have available other than free study space and coffee?
also, please note that this space will be available to you 24/7

>>8954177

thats just the definition. Its a definition that predates all the set theory and axiom stuff in the early 1900s.

you get one and only one output per input.

>>8954182

functions are super useful in computing. If you can verify that a process gets one output for each input, and that the output is consistent, you have a reliable process. unreliable processes cause bugs. The predicate function in logic has similar power. If a propositon is true, its always true, and its never true and false. All reasoning is functional.

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A non-scientific here.

How can I take away the fear of death from a cosmic event? It really terrifies me.

>>8957951
It would be instantaneous and there is literally no conceivable way for us to avoid them. Comfort yourself in knowing that at best it will never happen, as it hasn't happened for thousands of years, and that at worst you won't even have time to realise it happened.

Software engineering or computer science?

Computer engineer student. I got A in every subject, but failed in maths this year (first year). Should i keep going on with the studies or just quit? I absolutely hate math and it's so hard for me to retain the anything about the subject.

>>8952584
How can I get my body to stop producing alcohol dehydrogenase? For... academic purposes.

>>8957880
It's a mirror on a plane, not in 3D space, the line from 3 to mirror is best reflected by the line A to mirror, not 1 to mirror as it may be in 3D space.

How can you be this much of a brainlet?

Is it like a general rule I've never heard of that the antiderivative of a function of x times a constant is its derivative over the constant? its derivative with respect to the x*constant I mean.

so like
∫f(cx)dx = f'(cx)/c

examples
∫cos(5x)dx = sin(5x)/5
∫e^(2x)dx = e^(2x) /2

totally didn't post this in the dead thread without realizing there was a new one ahhaha

>>8958051
you're kind of like me, I just got done with first year too in comp eng. my issue is that I'm really really not good at math even if I want to be, I just can't fucking do it and I know that I need to be good at it.

it's like, programming is what I want to make a living doing and I have the inability to do it because I'll never get a degree because I can't do math

>>8958051
>hate math
>>8959869
if you faggets like programming and are bad in math then you obviously dont get what computer scientits/engineers are doing you fricking pricks.
Edsger Dijkstra "programming for a computer scientist is like telescope for astronomy"

>>8959874
I get it it's about algorithms and proofs and graph theory and whatever the fuck

I'm saying I'll never be good at it

>>8959864
pose y= cx, then express the integral (with the change of domains) in terms of y and dy

>>8954177
it's just the definition. without that restriction, youd just have the definition of a relation.
as for the usefulness, and why it deserves its own definition, think of pretty much any theorem or definition in analysis. how would you define the integral of a "function" with 50 odd outputs?

how does university grades scaling work? I'm quite confused by the whole thing. An assessment in one of my classes has a massively low average but the professor says not worry because it will be scaled, which I don't understand what she means

>>8959984
depends on how autistic your teacher is

Can someone help me with figuring out on what should I put emphasis on during my math self study, if my points of interests are geometry and topology? I´m pretty okay with college calculus. Also, some textbook recommendations would be be very nice.

>>8960536
Get rich so you can AFFORD self study first.

>>8952584
Why is 11, 23, 5 and many others considered prime numbers when you can evenly divide them, for example: you can divide 11 by 2 for an answer of 5.5 and 5 for 2.5. Any answers?

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WHAT THE FUCK FOR FUCK'S SAKE?!

>>8960598
What's your question.
T1 does equal T2 for the same string.

>>8960604
BUT IT'S EQUAL TO mg FFS. AND THEY ARE DIFFERENT.

[math]\mathbb{Z}/\mathbb{nZ}[/math]

Is it okay to pronounce this "mod n"?

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Is a degree by the Open University taken seriously by research institutes, universities and employers or would a degree from Bumfuck State University be dozen times more worth?

>>8961034
no because it's not clear what set you're taking mod n

I'd call it either Z mod n Z or Z mod n, or in the case you're only looking at the group structure, calling it Cn (the cyclic group of order n)

If f(x,y) is an arbitrary binary primitive recursive function, is the unary function d(x) = f(x,x) also primitive recursive?

It feels like it should be but I can't see how to construct the defining equation while ensuring that it has the correct arity.
(I'm using the definition in http://www.logicmatters.net/resources/pdfs/gwt/GWT2f.pdf which essentially states that if f(x) and g(w,u,y) are primitive recursive then so is g(w,f(x),y).)

How the fuck do I get a matrix into (Reduced) Row-Echelon Form? Is it literally just guess and check or is there some trick that I'm missing?

>>8961034
I usually say "integers mod n" or "Z mod n" or "Z n" (per the common notation [math] \mathbb{Z}_n [/math])

>>8961511
>per the common notation

that notation gets confusing when n is prime

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>>8952584
>Length contractions only contract in the direction of movement
>Lorentz transformations map circles/spheres to circles/spheres (Penrose 1958)

How the fuck? If a ship is moving inside a ring from a side to the opposite side, doesn't the ship see the radius in the direction of travel smaller than the orthogonal radius?

>>8952584
>tfw /sci/ will have generals now because of this shit
I don't want what happened to /v/ and /int/ to happen here.

>>8954393
What's the catch

How do I stop feeling emotion like Da Vinci?

>>8961754
/v/ and /int/ are usually more focused generals, this is an unfocused general which helps get rid of what would otherwise by hundreds of shit quality threads

Since a solenoid is pretty much an electrically controlled switch, you could in theory build a computer out of one, right? Like smaller ones than the one in a car.

Thinking about how to make computers from scratch, seems like a lot less material science required than vacuum tubes or silicone transistors

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/sci/ I'll know you'll laugh at me but I need help. I can't for the like of me get excel to turn this into a scatter plot. What's wrong with the order of my data?

>>8961787
pls help

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Do non-mathematicians fight about the order to list authors on their journal publications? Alphabetical seems so convenient in comparison

what was the most difficult concept you have covered in mathematics?

Im interestd in learning c++, I have very little knowledge of computer programming and have narrowed my choice of book to two.

The first is c++ primer, and the second is programming -- principles and practice using c++.

They're both advertised as beginner books but I', wondering if anyone here has a recommendation between the two.

>>8961906
the Picard-Lefschetz formula

still no idea what that was about

>>8956097
An image doesn't really exist. The object is at A and your looking into the mirror from wherever. Where does point A appear to be?

Pro-tip imagine that you don't know its a mirror and think its a window instead.

>>8961506
Google 'Gaussian Elimination'

>>8961927
Learn python

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Xenotransfusion-enhancement
Would it be possible if we transfuse silberback gorrila blood in our bodies (let's say both subjects are highly compatible) to enchance in any way our bodies or mind? (long or short term)
[Memory transference in organ transplant recipients] maybe it could work the same way with blood on a smaller or different level.

>>8961982
Embolism due to blood clotting.

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>>8961994
So there is no way to transfer blood (maybe low ammounts over a period of time or if that not works due to our based immune system a well calculated ammount) from a compatible silverback to a human?
>mfw I will never experience at least a glimpse of Grodd greatness

>>8962004
You have to match blood types even with human donors or the results will be fatal. For gorilla's who the fuck knows.

Even if you could you wouldn't absorb special powers. This isn't an anime.

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>>8952588
Doing an exercise in a Serg Lang book, and I'm confused, even if it shows the answer I'm unable to tell how he did it.
>Show that if n is a positive integer at most equal to m, then

[eqn] \binom{m}{n}+ \binom{m}{n-1}= \binom{m+1}{n} [/eqn]

The answer is pic related. I get how he got the LCD and +m!n. The other parts of the answer is leaving me frustrated. How did he get (m-n+1) to be on top of the fraction? How in the world did he turn
>m!(m-n+1)+m!n
to
>m!(m+1)

pls help a brainlet out

>>8962045
>How did he get (m-n+1) to be on top of the fraction?
if you want to add fractions you need a common denominator, in this case it's n!(m-n+1)! as he wrote

so

m!/[n!(m-n)!] + m!/[(m-n+1)!(n-1)!]
= m!(m-n+1)/[n!(m-n+1)!] + m!*n/[(m-n+1)!n!]

as for the second part

m!(m-n+1)+m!n
= m![ (m-n+1)+n]
= m![m+1]

>>8962053
>m!*n/[(m-n+1)!n!]
Ok I get this part, you multiplied n(n-1)! to get n!(m-n+1)! So whatever you do to the bottom, you do to the top so m!n

>m!(m-n+1)/[n!(m-n+1)!]
I DON'T get what you did here, by putting (m-n+1) on the top, that means you did
(m-n+1)(m-n)!n! on the bottom, which would equal [n!(m-n+1)!] ?

>m!(m-n+1)+m!n
>= m![ (m-n+1)+n]
>= m![m+1]
So did you just merge m! and m! together to equal m!? I get how you got rid of the n, since -n+n=0. The m! seems to just disappear out of nowhere.

>>8962069
>by putting (m-n+1) on the top, that means you did
>(m-n+1)(m-n)!n! on the bottom
no, you have to do the exact same to the top and bottom to preserve equality

m!/[n!(m-n)!]
= m!/[n!(m-n)!] * 1
= m!/[n!(m-n)!] * (m-n+1)/(m-n+1)
= m!(m-n+1)/[n!(m-n)!(m-n+1)]
=m!(m-n+1)/[n!(m-n+1)!]

>The m! seems to just disappear out of nowhere.
the m! doesn't disappear, it's still there at the end so I'm not sure what you mean

it's just factoring, ab+ac=a(b+c)

>>8956097
>where does point A appear to be?
>from wherever
um, doesn't the first depend on the second?

>>8962071
>= m!(m-n+1)/[n!(m-n)!(m-n+1)]
>=m!(m-n+1)/[n!(m-n+1)!]
Okay I was with you until this, [n!(m-n)!(m-n+1)] turns to [n!(m-n+1)!]?

>the m! doesn't disappear, it's still there at the end so I'm not sure what you mean
I mean there's two m!
>m!(m-n+1)+m!n
^ ^
The one on the right seems to disappear but the one on the left stays.

>>8962089
>Okay I was with you until this, [n!(m-n)!(m-n+1)] turns to [n!(m-n+1)!]?
yes, n! * (n+1) = (n+1)!, this should be clear from the definition of factorial

>The one on the right seems to disappear but the one on the left stays.
like i said, it's just factoring out m!, no disappearing

m!*b + m!*c= m!*(b+c)

What mind-altering chemicals should I take to rewire my brain into becoming full-blown gay?
Women are an idiotic waste of time and I'd much rather be sexually attracted to guys.

>>8962100
>What mind-altering chemicals should I take to rewire my brain into becoming full-blown gay?
fluoride

>>8962098
Alright got it. Thanks for your time and putting up with me. Appreciate it.

>>8960598
>>8960612
acceleration isn't zero

try calculate F for each block (F doesn't equal 0)

>>8961757
Mood stabilizers

Any sci fags smoke weed?
After living goodie two shoes my whole life I went out on my own and became a big pot head.

Going on 8 months now. Feeling groggy this am. Much slower than I was before.

What are sci-worthy pro's and con's to smoking marijuana?

>>8962232
weed is the devil's lettuce

also weed makes you lazy and laziness is bad for being smart

>>8961953
That's what I'm trying, but it's so hard. There's not really any rhyme or reason to it, and if I mess up I'll have to start all over.

>>8962336
>pick any row whose first entry is non-zero
>divide that row by first entry so that first entry is now 1
>subtract appropriate multiple of that row from every other row so that every other row has a 0 in that spot
>repeat with a row whose first coefficient is 0 and second is non-zero
etc..

So we've sequenced the human genome, what does that mean? Surely every individual has a different genetic code, is a species' genome an 'average'?

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>>8962348
Thanks, I think I understand it a little more now.
Pic related was the problem. I started with the matrix on the left, and I ended up with the matrix on the right. Did I make any mistakes?

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>>8962437
you can check with wolfram for a final answer

http://www.wolframalpha.com/input/?i=row+reduce+%7B%7B4,+-1,-1,0,75%7D,+%7B-1,4,0,-1,75%7D,+%7B-1,0,4,-1,25%7D,%7B0,-1,-1,4,25%7D%7D

yours isn't in RREF since there are columns with leading ones (i underlined them) that have other non-zero entries (circled) which isn't allowed, go re-read what RREF is exactly

>>8962455
I know it wasn't RREF, I just needed to get it into REF.

>>8960598
This is actually a very good question, both tensions have the same absolute values only if the string is ideal. Consider the case where you have the two different masses held by the same string, only that instead of a pulley you have the two masses moving alongside the x axis with the string in between experiencing a tension [math]\vec{T_{1}}=-T_{1} \hat{x}[/math] because of [math]m_{1}[/math] and [math]\vec{T_{2}}=T_{2} \hat{x}[/math] because of [math]m_{2}[/math] (on the right side of the string). Since under this cases we assume the string is inextensible and has no mass, we can use Newton's second law as
[eqn] m \vec{a}=0 \vec{a}=0=(-T_{1}+T_2) \hat{x}[/eqn]
and therefore
[eqn]T_{1}=T_{2}[/eqn]
Now for the tricky part: in your problem, instead of taking a typical cartesian coordinate system, you can take a system [math]\textbf{following the string }[/math]. This is something typically done with problems with pulleys and inclined planes, and can be done here. The thing is, if you accept your coordinate system can move around following the string (it can be a little hard to grasp at first) you can reduce part of the problem to the one I have stated before. Then, you can successfully state that [math]T_{1}=T_{2}[/math]. I know this isn't a rigorous proof or something, but at least is better than having to accept such a fact just 'cause.

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>>8962081
See how the rays appear to be coming from A'. That is the image of A and it appears to be coming from the other side of the mirror. It doesn't matter where the observer is.

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>>8962081
I hope this is a little better, and not more confusing.

>>8952584

What is the significance of long dividing an integer by a complex number?

I have recently read about base -1+i. Apparently all complex numbers and integers are representable in this base. To convert a number to base -1+i (which is binary with different place values), you divide out -1+i until you get a remainder of 0 or 1. You stop when it terminates and it evenly divides.

>>8962455
>>8962461
One more thing, does each matrix have only 1 unique RREF? I just tried it with another problem and I'm pretty sure I did it right, but I checked it on my calculator and the answer is slightly different.

>>8952584
Anyone know how to do this
>>>/wsr/327941

>>8962931
It's been a while since I've done a problem like this, but I believe coefficient of friction is just arctan(angle), so arctan(pi/3) = .808.
I'm not really sure about part b, but you'll probably want to use moment of inertia. Moment of inertia of a hoop about it's center is I = MR^2. Then you might use the relationship between torque and moment of inertia to find the angular acceleration.

t. no idea what I'm talking about.

Say I have the equation aN+c=S, where N is the set of natural numbers, a is a natural number, and c is a natural number. Does the resulting set S always contain an infinite number of primes, regardless of what values are chosen for a and c?

>>8954054
No. It is always conserved you just can't know what it is exactly. That might sound wrong, but it turns out that if energy wasn't conserved then the model wouldn't work at all actually. So even though it's uncertain we can know things like that because there would be no reason to take any of it seriously otherwise.

>>8963064
https://en.wikipedia.org/wiki/Dirichlet%27s_theorem_on_arithmetic_progressions

>>8962767
>does each matrix have only 1 unique RREF?
yes

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[Latex, beamer] guys help me please, I'm using beamerposter to make a poster and I get this strange line at the top of my block. Also, when I disable the rounded corners (rounded=false), the entire title turns into the color of the line. How can I remove it?

I failed a class for the first time in university. I thought I could do it, I thought it'd be easier. I feel like a brainlet.

>>8961721
https://en.wikipedia.org/wiki/Terrell_rotation

If smooth muscles can't be consciously controlled, and the muscles used in childbirth are all smooth muscles, what is the meaning of telling a woman to "push" during childbirth?
Is it not asinine to tell a woman to do something that she physically can't do?

>>8963284
this is a stupid QUESTIONS thread, not a stupid people thread

What is the evolutionary advantage of blood cells being made in the bone instead of some other organ?

Is there a place online to discuss number sequences?

How do I use Eulers formula? I didn't understand it. What is the purpose

>>8963588
You have more bones than organs in your body. If one organ made blood cells and that organ failed, you die.
If every bone makes blood cells and one bone fails you don't die.

>>8963601

Yeah, but could you say that about every organ which has a critical function it only does. (e.g. the heart, kidneys)

Also there are other "organs" that are widespread throughout the body, skin for example. So why didn't another organ (It can be a new one) that was situated throughout the body develop that only dealt with creating red blood cells?

>>8963605
Because god made it so

>>8963599
e^x=cosh(x)+sinh(x)

>>8952584
do gas clouds in space also expand with the space or do they stay the same size like stars and planets?

where do i start with complex analysis? do i need to know a bit of topology beforehand?

>>8964071
>where do i start with complex analysis?
any complex textbook

>do i need to know a bit of topology beforehand?
only basics like open, closed, compact sets

Hey /sqt/, Im looking to get into plasma physics a little more, as well as learn some more about electrical and optical properties of materials as it relates to plasma like states. With that, what are some good textbooks for learning more about electrical and plasma systems? I have a decent working knowledge on it (taken a couple basic physics courses and one solid state one) but would like to build on it. I would prefer if it doesnt rely too heavily on external experience, thoush some basic things that are expected is fine.

>>8963773
>what is gravity

Can I learn classical mechanics so that I can pass a course on it in 5 days?

I know how to derive the Euler-Lagrange equation from an action but that's about it.

How do i express x^2 + y^2 = 100 in R^3 (3D)?

Since z doesnt exist, how do i convert it to cylindrical coordinates and spherical coordinates?

My instinct tells me a 3D plot of it will be a hollow cylinder, but i cant create a function that includes z which creates a hollow cylinder.

What am i doing wrong?

What mathematical trick do I have to use to find the pattern here?

{ "Rank 991", 46891700 },
{ "Rank 992", 46964850 },
{ "Rank 993", 47038050 },
{ "Rank 994", 47111300 },
{ "Rank 995", 47184600 },
{ "Rank 996", 47257950 },
{ "Rank 997", 47331350 },
{ "Rank 998", 47404800 },
{ "Rank 999", 47478300 },

Please explain me so I can do it alone next time.

>>8964456
Plot it?

>>8964412
It is a hollow cyl

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>>8952584
Is there anything special about the point where f(x) = integral [0, x] (f(x))? I realize e has this property but I'm wondering about other functions. I also feel like an increasing function should generally have exactly 1 such point but don't know how to show that,
Didn't get an answer in the last one. Thanks!

>>8964467
since z = 0, how do i express this in cylindrical and spherical coordinates?

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>>8964516
this picture is the wrong problem sorry. The right side should be the same function as the one being integrated.

>>8964516
if f(x)= ax^n then int f(x) = ax^(n+1)/(n+1) so the special point is at x=n+1

also notice that when this point exists for a function, it's also a special point for any multiple of the function

i.e. if g(z)=int g(z) and f(x)= c*g(x) for some constant c then
f(z) = c*g(z)= c*int g(z) = int c*g(z)=int f(z)

>>8964606
>>8964516
also some increasing functions have more than one

consider f(x)=2x-6
then int f(x) = int 2x-6= x^2-6x
and 2x-6=x^2-6x has two positive roots 4 + sqrt(10) and 4-sqrt(10)

Which course should I choose for the next semester? Advanced linear algebra, advanced geometry, differential geometry or circuits analysis (I'm in a physics degree).

>>8964672
advanced lin alg if you haven't done quantum yet and aren't that comfortable with lin alg

diff geo if you haven't taken general relativity yet

what's advanced geometry?

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What are the best things I can do to make myself stand out when applying for medical schools? Obviously excluding GPA and MCAT scores.

>>8964644
thanks! Are there any applications for these points that you know of?

>>8964672
Link to the course descriptions

>>8961927
>Programming: Principles and Practice Using C++ by Stroustrup (Written by the creator of C++. An excellent introduction to programming and to C++)
>C++ Primer by Lippman, Lajoie, and Moo (Works as ... a first book on C++ with some prior programming experience)
>http://4chan-science.wikia.com/wiki/Computer_Science_and_Engineering

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Proving that the wavefunctions Ae^(inx) and Be^(imx) are orthogonal when n!=m, I'm too rusty on my Calculus to remember how to integrate this

>>8965054
literally trivial, why are you studying wavefunctions when you can't integrate exponentials?

>>8965033
nope but there might be

if you consider functions that are both increasing and positive on [0, infinity) you might be able to have a unique point but i'm not sure

>>8965063
Forgive me for not remembering what identity I should be using to deal with the imaginary part

>>8965073
integral of e^ax is e^(ax)/a for all complex numbers a

>>8965077
a non-zero of course

>>8960536
>Matrix Algebra
http://joshua.smcvt.edu/linearalgebra/
>Vector Calculus
Calculus of Several Variables by Lang
>Geometric Algebra and Calculus
Linear and Geometric Algebra by Alan Macdonald
Vector and Geometric Calculus by Alan Macdonald
>Proofs
A Transition to Advanced Mathematics by Smith, Eggen, and St. Andre
or
http://www.people.vcu.edu/~rhammack/BookOfProof/
>Group Theory
Groups and Symmetry by Armstrong
or
Visual Group Theory by Carter
>Linear Algebra
Linear Algebra by Shilov (Dover Book)
or
Linear Algebra by Hoffman and Kunze
>Modern Geometry
Geometry by Brannan
>Curves and Surfaces
Pressley's Elementary Differential Geometry
or
do Carmo's Differential Geometry of Curves and Surfaces (Dover Books)
>Analysis
Zorich's Mathematical Analysis I && II
>Topology
Principles of Topology (Dover Books) by Croom
or
Elementary Topology (Dover Books) by Gemignani
>Linear Algebra and Geometry
Linear Algebra and Geometry by Kostrikin and Manin
Linear Algebra and Geometry by Shafarevich and Remizov

I have 55kg and 180cm. I wanna know if I can carry on my arms a 60kg girl? I tried to ask on /fit/ but it seems to be a more physics/math question to me

>>8965106
Whats your SPD? You probably will need at least a SPD of 2 or more

>>8965156
What is SPD? Sorry

>>8965170
Scoops Per Day.

>>8965172
Currently none. If so, I cant do it, right?

>>8965176
Afraid not Anon, you should never be at a SPD of 0, bare minimum is 1.

>>8965179
Thanks but, why taking it improves my capacity of carrying her? I mean, im also not doing any lifting,etc.

Does time exist in a four dimensional way the same way that other space dimensions exist.
I mean, the way I see it, every instant in time of this Universe is actually a "frame" of the Universe in that given instant, and there is an infinite number of those frames, as there is an infinite amount of instants. Think of it like one of those old movie rolls that are made of a quick succession of pictures. What happens when you pile up hundreds of two dimensional pictures one over the other? They start looking more and more like a cube right? So couldn't each instant in this 3D universe actually be just a picture that is piled up infinitely forming a 4 dimensional thing called spacetime?

>>8965283
time to put down the bong

>>8965285
I don't use drugs, however, I must warn you I am on the spectrum, and have HS level education. My question was serious. The way I see it time is actually a collection of "Universes" "paused" in infinitely distinct instants. The same way a lot of 2D pictures that are shown in a certain fashion cause the feeling of time to someone watching a movie, and the same way if those pictures are piled up they'll look more 3D than 2D, it's how I perceive time as a whole. That is to say tomorrow already happened, tomorrow has always happened, and will always have happened. It happened at the same time as both the beginning and end of "time".

>>8954050
No, space increases everywhere, but gravity is so strong, that its only relevant at the big scale, where relatively there is far more space than matter than in the small scale.

I'm a black-haired Asian, but every now and then, I find a red hair on my head/face.

Is there any reason why this would happen? I don't want to jump to any conclusions with my ancestry (that's a copout response and it's farfetched anyway), and I'm genuinely curious as to why my hair would be any other color.

>>8952588
Algebra Chapter 0

If I made a function that takes two variables (a,b) and returns one if a is divisible by b and 0 if not, is there a way to use that function to create another function that lists the factors of a?

>>8965554
[math]b^{f(a,b)} [/math], will do the trick, to get it into a list, all you need to do is take all values [math]b = 1, 2, \dots , \frac{a}{2} [/math], and get rid of all the excess 1s. In a programming setting, it means running a forloop and testing for the values [math]b^{f(a,b)} [/math] for the aforementioned values of [math]b[/math], if you encounter something other than 1, add it to your growing list.

>>8965360
you're getting raped in your sleep by a qt ginger
occam's razor

>>8965651
f(a,b){
return not (a modulo b)
}

factor(a){
for (b=2 to a/2)
-if f(a,b)
--return list(b).append(factor(a/b))
-end if
end for
return list(a)
}

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As a student I would like to ask

Why are exams so much more difficult than the homework and lesson examples in math?
Whatever math class I ever took - the final exam was on a whole different level.
I don't know if it's a German thing or if it's everywhere like that.

If so, what does it take to 'master' final exams?

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How can the sum of a series be estimated using an integral. How is this move legitimate?

>>8965732
Indef integrals are actually just series, so what you're seeing is just an analysis theorem that they didn't explain.

>>8958051
At this point just kys.. improve the gene pool

>>8959876
You will be if you stop being a faggot and use different strategies to learn.

>>8960612
Because both ends are attached by a pully you moron.

>>8961906
Tensor products (not the faggoty analysis kind)

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I'm doing pic related and answering all odd numbered questions. However the book contains answers for even and odd questions in the review sections. Does this mean I have to do ALL the review questions or can I just do all the odd numbered ones? If I do all questions that's like 100 review questions per section. Hope this makes sense

Do you need any experience to get into undergrad research? Two different professors at my uni are looking for undergrads for their group and the topics sound interesting (photonics and electromagnetics), but I havent taken classes on either yet. Im about to be a junior and will be taking an electromagnetics related class in the fall. Do they care about this at all or do they just accept people with interest in the topic? Btw there is no "application", just have to email the dudes a resume

>>8966073
>Do you need any experience to get into undergrad research?
yes, you should at least a PhD, a few letters of reference, a few years of experience working in the field and be willing to work for no pay at the start to prove your worth

>>8965744
thanks mate

>>8965651
is there a way to do it with less computing power

>>8966075
I just mean like do you typically need certain courses before they let you in

How do you master a subject in University?
Basically that you are guaranteed to pass this class with a good grade.

>>8964518
Cylindrical: r=10
Spherical: r=10*cot(φ)

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How can you sterilize a surgical set at home?
I was thinking of soaking the kit in bleach for 10 minutes then putting it in oven on 200C for 60 minutes.

>>8966226
putting it into the dishwasher with standard cleaning and a subsequent 30 min bath in some store-bought liquid desinfectant should do the trick.

How many cells are there in a 1 mm cubic piece of tissue? A million?

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>>8964681
showing an initiative for getting things done and seeking out work to improve yourself. volunteer work always looks good for reference! veterinary volunteer or pet shelter volunteer work is (almost??) always available and very low stress if you have no experience working in human healthcare or hospice.

>>8966226
>How can you sterilize a surgical set at home?
Strictly speaking, I don't think you can - the over itself isn't sanitary. >>8966229 might do the trick.

Don't do surgery at home, anon

>>8966233
you have to be more specific about the type of tissue.
"How big is a cell?
There is not one single answer to this question. Why? Cell size varies depending on where it comes from and what it does. This means that a bacterial cell is samller than an animal cell, a human red blood cell is smaller than a human nerve cell and all of these are smaller than the single-celled, 15cm long ostrich egg!" ~ http://www.lsu.edu/science/soar/files/how_big_is_a_cell.pdf

>>8966229
Will washing with a teeth brush then soaking in Chloroxylenol do the trick?
>>8966250
>the oven itself isn't sanitary
I realize that.
>Don't do surgery at home, anon
I just use it to suture wounds, and the toothed forceps gets bloody sometimes.

>>8965672
it might be a german thing. at my uni the homework is far harder than the exams, which is the best way around i think.
do you have access to your uni's past papers? if not, other universities' papers can be helpful to practice on, especially unis ranked higher than yours.
for my maths exams www.maths.cam.ac.uk/undergrad/pastpapers has been invaluable

>>8966268
you didnt answer my question for shit yo. i didnt ask for a piece of ostrich egg. tell me about solid lung or gut tissue or maybe even a tumor.

>>8966274
Will washing with a teeth brush
yes but with soap
> then soaking in Chloroxylenol
just use some sagrotan or even desderman, or 80% alcohol, maybe with little detergent added.

>>8966019
anyone?

>>8966341
you not have free will or something? do however many questions you want

Just got a C in microeconomics. Am I fucked? Business Finance/Accounting here.

>>8963398
dude she can support the process with her voluntarily-controlled muscles

>>8963588
dude they are made in fetal liver first when you are unborn
but the liver is used for some other stuff later

>>8962232
>What are sci-worthy pro's
you get to know what it is and having experienced its effects once or twice helps you understand some advanced neuroscience and the drug's role in society
> and con's to smoking marijuana?
everything, litraly everything with mj is bad for you if used regularly, for longer periods, or in the young brain

?Linear motion is absolute but rotational not.

What level of math do I need to start studying real analysis?

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I'm trying to analyze the dynamics of the function [math]f(x)=\frac{4}{\pi}\arctan x[/math] under iterated function composition.

First, I want to find the fixed points, i.e. where [math]f(x)=x[/math].

Just looking at the function (and knowing from experience that [math]\tan(\frac{\pi}{4})=1[/math] and [math]\tan(-\frac{\pi}{4})=-1[/math]), it seems obvious that the only fixed points are -1, 0 and 1.

But is there an elegant way to argue analytically why these are the only solutions other than "look at the graph"?

>>8966743
you could do something like playing around with derivatives to look for any fixed points in-between fixed points you already know, the main idea i guess is considering how many times you have f'(x)=1, since if f(x) > x and f'(x) > 1 on an interval then there can't be any fixed points, similarly if f(x) < x and f'(x) <1 on an interval there can't be any fixed points there

let g(x)=x, then g'(x)=1 and f'(x)= 4/(pi (1+x^2))

we have f'(-1) = 2/pi < 1 = g'(-1) so you know g(x) > f(x) in a small neighbourhood to the right of -1

taking this further since f'(x)<g'(x) on the interval (-1, -sqrt(4/pi -1))there's no fixed points in that interval

since f'(x)>1 on (-sqrt(4/pi-1),sqrt(4/pi-1)) there's at most one fixed point there ( which you already know is x=0)

similar argument as before gives no fixed points in (sqrt(4/pi-1),1)

hopefully that makes some sense

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I desperately need help. I have a final in forty minutes and don't completely understand how transistors work.

In pic related, why would there be no current everywhere (except [math]I_3[/math], but I understand why I3 would be -5mA)?

Throwing this out there because I need all the help I can get:
I understand how "not" logic gates work, but how do NAND gates work? How does putting two PMOSes in parallel and two NMOSes in series give you NAND?

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>>8966893
Pic related is the NAND gate I'm talking about

>>8966893
Because the gate looks exactly like the diagram shows. It's not connected to anything so no current can flow (besides capacitive leakage) so i1 & i2 & i4 & i5 are open. i6 has no current because on the left is 5V and on the top right is 5V so the voltage across the resistor is 0V.

>>8966902
N-types turn on with positive voltage
P-types turn on with negative voltage

If both A&B are true/high/positive then both NMOS turn on connecting the output to false/low/negative aka not (A and B == true).

If either A or B are false/low/negative then the corresponding PMOS turns on connecting the output to true/high/positive and one of the series NMOS turns off disconnecting the output from the false/low/negative.

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>>8966923
>>8966931
THANK YOU. ABOUT TO TAKE MY FINAL IN FIVE MINUTES. FUCK

>>8966825
Yeah that sounds reasonable, thanks for the help.

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>every element of C is mapped to by at least one element of A
>no two elements of A map to the same element of C

So the composition is bijective, which implies the first function is injective, right? Except clearly it's not. Where's the flaw?

>>8967090
the composition isn't defined since you didn't define a function from B to C since you didn't say where 2 goes

>>8966224
i'm still confused :(

how does plotting x^2 + y^2 = 25 in R^3 work when there is no z component?

it's a hollow cylinder, but there is no z in the equation.

i'm confused how this works.


also in R3 how do i make a xyz equation to create a hollow cylinder like the xy one does?

>>8967151
there's no z, so as long as x^2 + y^2 = 25 then any z value works

>>8952584
How did they weigh the earth?

>>8967157
so it is just a circle with a radius of 5 at every point on the z axis?

and how do i express this in spherical component?

i do x^2 + y^2 = 25
x = Psin(phi)cos(theta)
y = Psin(phi)sin(theta)
z = Pcos(phi) but doesnt exist

so [Psin(phi)cos(theta)]^2 + [Psin(phi)sin(theta)]^2 = 25
and [Psin(phi)]^2 = 25
Psin(phi) = 5

this is the best i can do

>>8967173
>so it is just a circle with a radius of 5 at every point on the z axis?
yes

Hey, I am in Electrical Engineering and I am applying for grad school. My overall GPA is 3.7 and my department GPA is 3.75. I took my GRE and I got weird results. I am in the 93rd percentile in writing and a 92nd percentile in the verbal part. That is pretty good but I am in the 55th percentile in the quantitative part, which is awful for an EE. I chose not to send this out the scores to schools I was eyeballing, as I sure as shit don't qualify based on my math score.

Should I retake the test? Does my very high verbal and writing score count for anything? Does my GPA weigh more than my GRE math score by a good margin?

How do you compile TeX files? I've used LaTeX for years (granted, without much knowledge as to the inner workings), but I'm working with a manuscript that just uses straight TeX, and normal compiling methods just throw a bunch of errors (I just need to make minor edits so I don't need to become an expect, just to be able to compile the damn thing).

>>8967166
Weight of the Earth doesn't really make sense. Weight is dependent on gravity. If you weighed yourself on Earth and then on Mars, and then again on the Moon you'd have a bunch of different weights. You mean mass.

Mass is the amount of stuff that composes something. Your mass doesn't change based on what planet your on, but your mass multiplied by gravity is your weight. I get the confusion though. Both mass and weight are measured in kilograms, but they mean different things.

But to answer your original question, they used the equation for gravitational forces to determine Earth's mass based on the amount of gravity it has.

http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Mass.shtml

>>8966737
A solid understanding of calculus really. Download some books on calculus and real analysis and if you don't understand something, try looking it up somewhere else or in another book.

>>8967180
i'm not an EE, but for any kind of applications/grad stuff, you want to be well-rounded

the thing is there are probably people applying who got 90s in all 3, or 80s in 2 and 90s in quant, or 60s in 2 and 90s in quant, etc.

i cant say whether or not to retake it, but if you give them this result, it could be used against you, likely more often than it could be used to help you (since quant is big for stem)

>>8966737
You need mathematical maturity. It shouldn't be your first proof based class nor your second.

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Hypothetical situation.
= A diver is put into huge water ball. The ball is placed on a slope 1000m high.

What would happen to the diver? Would he remain stationary while the ball is rolling down or would the water that has contact with the balls surface slowly start stirring the water inside the balloon thus making the diver spin too?

What evidence is there, at all, for String Theory?

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>>8967498
string theory can't be wrong if it's too expensive to test

>>8967467
Yeah, reading around I might have to. I may get a grant that will pay for tuition and books in grad school but only if I go to my safety school. My safety school already told me I am in no matter what my GRE says. I have already taken 2 grad classes already and will have 3 more before I graduate, if that counts for something since I got A's in both of the grad classes that I have already taken.

I was right not to send my scores out if I want to get in a better school. Apparently no one gives a shit about a high writing and verbal score. My quantitative score will send my application straight into the garbage.

>>8967494
The diver would start spinning too.

If I bachelor in both Computer Science and Civil Engineering what kind of specialized industry can I join? Something that only someone with those two could do very well.

>>8967670
>Computer Science

Literally a brainlet degree.

>>8967685
Thanks you must be feeling really edgy now but can you please answer the question

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>>8952584
I'm a mathlet, why can't pic related be simplified to r + s ?

>>8967707
because r^2+s^2 =/= (r+s)^2

>>8967688
>edgy

CS is as difficult as a business major.

>>8967707
Tell me what [math](r+s)^2[/math] is equal to

>>8967715
They score higher on standardized tests than business and tend to make more money.

>>8967498
None, though there are reasons to study it, namely it has produced many tools for physicists and mathematicians to use and has spawned off fields of study independent of string theory, frankly its a treasure trove of interesting ideas and useful constructs. There has been work done however to see if any consistent unified theory must be a string theory, and it actually has been proved that in certain models (models mind you that don't reflect our universe) string theory is the only possible unified theory of physics, and as such considering it's vast applications to physics coupled with it, in some cases, being literally the only possible theory, people have strong suspicion that it's true, though again, this is not evidence.

>>8966344
>you not have free will or something?
do not utter those words on this board

>>8967734
True, free will doesn't exist as it is all biological.

Any R users here?
Can I do some type of try/catch or try/except mechanisms in R?
I want to try and do something like this:
try (my_function())
if successful, continue
if not successful, do something else

Sorry for the shitty pseudocode, I'm obviously not big on these things.

>>8967384
> Both mass and weight are measured in kilograms
Mass is measured in kilograms, weight is measured in Newtons.

The confusion seems to arise from measuring weight (spring balances and load cells measure force) then converting the result to a mass based upon g=9.81 m/s^2.

>>8967940
>how much do you weigh?
432 N
>fatty.

Which to specialize in grad school if end goal is research/development in industry or national lab? Narrowed options to: electromagnetics/rf circuits or optics/photonics

>>8967980
If you're currently taking an undergrad, ask some of your professors. If you're not even taking an undergrad yet, take physics and then ask some of your professors.

How bad is a BCS in an Ivy League if I'm thinking of working in the industry? Not necessarily Google and Facebook, but at least non startup companies, working in the IT department of well established companies. Can I expect a 80k> income? I know CS in an Ivy is not CMU but how is it for getting a job?

>>8968048
Watch short YouTube videos on "time dilation" as you wait for a proper response.

>>8968048
underage b&

>>8953838
>that the lazy cunt who creates these threads sucks at his job
It's not like they're paying him

>LITERALLY NOBODY ANSWERS ANYTHING MORE COMPLEX THAN FIRST 10 (MAYBE 11) GRADES EVER
>implying this is in any way different

>It was like a day straight with no sqt.
Oh no, what ever shall we do?

what is the best 'online course' website? I have free time but struggle to teach myself with textbooks and really need structure and direction that a course offers. I tried edx but it feels a bit too unorganized and you can only go as fast as they put out the material. Ideas?

>>8968120
http://coursera.org/
http://udacity.com/
https://ocw.mit.edu/

>>8967859
why would you wanna do something like that on R? It's specifically for statistics, I can't think of anything that would require that.

>>8968042
Help.

how do I find the indefinite integral of something like x^7 * (1-x)^10

no idea where to even start

I mean obviously besides multiplying out (1-x)^10

>>8968261
https://en.wikipedia.org/wiki/Binomial_theorem#Theorem_statement

>>8968263
that's the only way?

>>8968270
probably not, but it's an easy way

Doing exercises and got to this.
>a)Find a positive rational number, expressed as a decimal, whose square approximates 2 up to 3 decimals
>b)Same question, but with 4 decimal accuracy instead
I don't understand the question lads, what does he mean by this?

>>8968261
also make the substitution u = 1-x so you only have to apply the binomial theorem to 8 terms

>>8968312
What kind of exercises is this? My gut reaction is that they want you to truncate [math]\sqrt{2}[\math] to a few decimal places, but that just seems weird.

>>8968315
Looked at the answers to see what he wanted me to do, all it says is the answer to
>b)Same question, but with 4 decimal accuracy instead
is, a=1.4141

>>8968333
kek
The question is literally "Write [math]\sqrt{2}[/math] to 4 decimal places".

Guys, how do I calculate the flow rate between two containers of gas with different pressures, taking into account the surface of the opening between them? I need to make a very simplified simulation of air pressure equalization.

>>8968394
Why is it 1.4141 instead of 1.4142?

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OK, so I don't know if u guys answer biology questions but an acquaintance of mine posted this picture of her new nephew . And I was wondering can humans this eye color? Or is it like cats and the eye color changes?

>>8968452
we evolved a sense of cuteness so we would want to protect our chil-

ok i'm so confused right now.
i live in a student dorm and we have these laundry machines that take 2€ coins.
my mom gave me 50€ worth of 2€ coins so i have enough to wash.
but now i'm thinking i already used up about half of them.
wait a second, half of them? wouldn't that be 25€? wtf? that's not divisible by 2.
i'm literally so confused right now, please help me. how can i have spent half of the 50€ when that's impossible to do with 2€ coins

>>8968467
You didnt spend 25. A dollar went missing somewhere.

>>8952584

My classmates are fucking annoying, they are always asking me things like i'm the teacher. How can i stop helping them without looking like a dick? I can't tell them to fuck off because we have to do some projects together

>>8968507
>How can i stop helping them without looking like a dick?
grow some balls

> I can't tell them to fuck off because we have to do some projects together
stop helping them unless it's for a project

>>8968507
dude wtf? you gotta help the community out and make sure everyone understands the material. you can't just let them study on their own, they're clearly too dumb for that. they NEED you.

>>8968507
tell em you'll explain over some beers, make some friends you autist

>>8952584
What is the difference between calculus and analysis?
I read "calculus is analysis without proofs", so students of calc 1-4 just do computations of problems without any proofs nor knowing what all those calculations built on? Why not start with calculus AND proofs and have a fundament to build on?

>>8968434
The "resistance" of a pipe depends upon more than just its diameter. Length, friction and drag coefficient all affect it.

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>>8968877
>calc 4

>>8968901
>>8968877
I have no clue how "far" calc goes, I am from the land where the rapefugees come to.
But I didn't get a answer to my question

>>8968901
>>8968919
Well, ok it seems because in HS most don't learn a lot of analysis/calc and then at least for 2 courses you learn to diff and integrate 1-n dimensional functions. makes kinda sense; "we" only learnd that for 1D -> 1D in HS

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What is /sci/'s opinion of pic related?

>>8968979
Never heard of that in particular, but the game theory course I took in uni was one of the best courses I've ever taken.

is University of Rochester actually the best university to go to for MS/PhD if I want a career in optics or is it just a meme? Many say that it is the best for optics, but would a MS/PhD in EE with a focus on optics/photonics at a top school like UMich get me the same or better opportunities?

What's more efficient, given the same surface area, and ruling out initial cost, photovoltaic solar cells, or mirrors and some kind of thermodinamic engine like a Stirling

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How do I find the radius of the circle? The big square has a side length of 3 and the small one has a side length of 1

>>8969166
prove that top right corner is congruent to the square in the corner

then find radius

>>8969166
ill do you one better: use highschool trig to find this one out

draw a 1:3 ratio from the small square to big square

find area of circle
find area of square

use trig

>>8968447
The question doesn't imply that there is only one correct answer

>>8969185
sqrt2=1.41421356...
So wouldn't 4 decimal places be 1.4142 as suppose to 1.4141?

>>8969224
>a)Find a positive rational number, expressed as a decimal, whose square approximates 2 up to 3 decimals
>b)Same question, but with 4 decimal accuracy instead

[math]1.4141^2 = 1.99967881[/math]
[math]1.4142^2 = 1.99996164[/math]

Rounding them both to 4 decimal places gives the same answer, 2

Are there limits to how many minors I can get? I mean, for example, is it possible to get a bachelor in , say, physics, with three different minors each in math, biology and chemistry?

>>8969338
depends on the school

If gravity is real how are we standing up

Assuming the matrix I −M is invertible, find an expression for v given that
v = Mv + w.

>>8969402
seriously can't get it? just pretend they're all numbers instead of matrices or vectors

>>8969405
I happen to be retarded I think.

>>8969402
Just think of M(v) as a vector as well.
v - M(v) = w
I_m(v) - M(v) = w
(I_m - M)(v) = w
v = w (I_m - M)^(-1)

>>8969408
I dont get matrices either. Like I understand if it asks me 'find the rref of this' but when it comes to these 'conceptual questions' I just blank

>>8969422
Thanks.

Bump limit reached
New thread here >>8969578

>>8969657
> 312
Pathetic ploy of sqt-retard to confuse people with samefagging. Yet another proof that he's not doing it to help people, he's in it FOR FAME. Fucking petty.

Two bodies - the first weighing 50 grams and the second weighs 100 g - thread bound and lying on a smooth horizontal surface. What is the largest horizontal force can pull the first body without tearing the thread apart? The thread stands 6 N of tension.

WHY THE FUCK IS IT 9 FFS?!

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could nuclear fusion potentially cause an extinction level event?

Is the biological species concept the most applicable way to define species? If si, at what point does a species diverge into two in the context of the differences between their genomes? Is there a specific locus or chromosome in which this reproductive isolation is accelerated?

>>8970073
the bump limit is 310

https://a.4cdn.org/boards.json