/sqt/ /qtddtot/ - stupid questions thread

[Anonymous No.15052868]

Previously >>15034337

>what is /sqt/ for?
Questions regarding maths and science. Also homework.
>where do I go for advice?
>>>/sci/scg or >>>/adv/
>where do I go for other questions and requests?
>>>/wsr/ >>>/g/sqt >>>/diy/sqt etc.
>how do I post math symbols (Latex)?
rentry.org/sci-latex-v1
>a plain google search didn't return anything, is there anything else I should try before asking the question here?
scholar.google.com
>where can I search for proofs?
proofwiki.org
>where can I look up if the question has already been asked here?
warosu.org/sci
eientei.xyz/sci
>how do I optimize an image losslessly?
trimage.org
pnggauntlet.com
>how do I find the source of an image?
images.google.com
tineye.com
saucenao.com
iqdb.org

>where can I get:
>books?
libgen.rs
z-lib.org
stitz-zeager.com
openstax.org
activecalculus.org
>articles?
sci-hub.st
>book recs?
sites.google.com/site/scienceandmathguide
4chan-science.fandom.com/wiki//sci/_Wiki
math.ucr.edu/home/baez/physics/Administrivia/booklist.html
>online courses and lectures?
khanacademy.org
>charts?
imgur.com/a/pHfMGwE
imgur.com/a/ZZDVNk1
>tables, properties and material selection?
www.engineeringtoolbox.com
www.matweb.com
www.chemspider.com

Tips for asking questions here:
>attach an image (animal images are ideal, you can grab them from >>>/an/. Alternatively use anime from safebooru.donmai.us)
>avoid replying to yourself
>ask anonymously
>recheck the Latex before posting
>ignore shitpost replies
>avoid getting into arguments
>do not tell us where is it you came from
>do not mention how [other place] didn't answer your question so you're reposting it here
>if you need to ask for clarification fifteen times in a row, try to make the sequence easy to read through
>I'm not reading your handwriting
>I'm not flipping that sideways picture
>I'm not google translating your spanish
>don't ask to ask
>don't ask for a hint if you want a solution
>xyproblem.info

[Anonymous No.15052899]

Unanswered questions:

Maths questions:
>>15039597 [I don't understand anything.]
>>15039865 [See above.]
>>15043320
>>15049617
>>15050124
>>15051276 [Don't think so.]

Physics questions:
>>15038740
>>15038811
>>15040028
>>15043267
>>15045395
>>15050030

Chemistry questions:
>>15043383
>>15044680

Biology questions:
>>15035040
>>15036149
>>15043204
>>15043573

/g/ questions:
>>15045335

Engineering questions:
>>15045375

Stupid questions:
>>15034404 [Correction in >>15034405]
>>15043272
>>15044963
>>15045237
>>15051604
>>15051962

[Anonymous No.15052925]

"Two cards are drawn successively without replacement from a well-shuffled deck of 52 card . Find the probability distribution of the number of aces."
The solution I came up with and the solution that I see everywhere online is to simply construct a table of probabilities for each possible case.
But that just feels dumb, isn't there a way to generalize the solution with a formula?
I mean, what if there were 20 aces, and I had to pick 20 cards, and I wanted to know the probability distribution of the number of aces? Would I really have to calculate every possible outcome?

[Anonymous No.15052950]

>>15052925
Hypergeometric distribution.

[Anonymous No.15052952]

>>15052950
Thank you anon.

[Anonymous No.15053196]

>>15039597
>>15052899
>I don't understand anything.
I think this anon is asking about the inverse of a piecewise function such as [eqn]f(x)=\begin{cases} x & \text{if }x<a \\ x+1 & \text{if }x\geq a \end{cases}[/eqn]For some constant [math]a[/math], the inverse of which is
[eqn]f^{-1}(x)=\begin{cases} x & \text{if }x<a \\ x-1 & \text{if }x\geq a+1 \end{cases}[/eqn]And this is indeed strictly increasing.

This anon seems to have gotten confused and incorrectly thought the inverse was [eqn]f^{-1}(x)=\begin{cases} x & \text{if }x<a \\ x-1 & \text{if }x\geq a \end{cases}[/eqn]Which is not strictly increasing.

[Anonymous No.15053253]

Is there an easy way to tell if an integer's prime factorization only consists of 2s and/or 5s?

[Anonymous No.15053274]

>>15053196
Thank you.

[Anonymous No.15053352]

>>15050030
[math] \displaystyle
F=-kx \\
F=ma \\
a=\frac{d^2}{dt^2}x \\
m \frac{d^2}{dt^2}x + kx = 0 \\
m \lambda^2 + k = 0 \\
\lambda = \pm i \sqrt{\frac{k}{m}} \\
x = c_1e^{i \sqrt{\frac{k}{m}}t} + c_2e^{-i \sqrt{\frac{k}{m}}t} \\
x = \cos \left( {\sqrt{\frac{k}{m}}t} \right)
[/math]
something like this iunno its been a while

[Anonymous No.15053360]

>>15040028
>How often does a new moon occur
roughly once a month, the period of the moons orbit around earth
>is a new moon always not visible?
is a shadow visible?
>>15043267
not sure why this is in physics
https://en.wikipedia.org/wiki/Interlaced_video#Interlacing_problems

[Anonymous No.15053362]

>>15052868
im an EE (electronics not electrical) student, kind of thinking about switching to CS (it's called something like computer engineering in my country, i dont know if its the same)

can anyone read this post and tell me what's the best fit for my interests between electronics engineering and CS? im a bit confused

i chose electronics because i wanted to be able to make my own projects and i like robotics. I dont know exactly what I like and what I want to specialize in, but i did like the intro to informatics course, especially the part about operating systems and cpu architecture.
I find computers fascinating, especially when it gets really low level if that makes sense, that's why im also interested in old technology (like the c64 for example, you have more freedom than on a modern pc with a modern OS)
i want to know deep down how computers work, how to create a whole operating system out of nothing (i dont want to actually do it of course, i just want to know how i would do it), how cpus operate in depth, one of the electronics projects on my checklist would be a homebrew cpu.
about CS i also like the concept of AI (and i see that in my EE master i would have a course called "HARDWARE ARCHITECTURES FOR EMBEDDED AND EDGE AI" but that's about it I think.
i dont really care about all of the other topics that are treated in a CS degree, like creating any software or website or even anything about the internet.

sorry for the blog post, thanks if anyone read

[Anonymous No.15053366]

>>15053362
would it be possible to provide a list of some of the courses in your "computer engineering" program? in the states, a typical CE program would be exactly what youre looking for, but a typical CS is definitely not.

[Anonymous No.15053391]

>>15053366
Bachelor:
1st year
>Mathematical Analysis
>Linear algebra
>Fundamentals of CS (this is 99% C programming and a few lessons on general CS)
>physics
>circuit theory
>fundamentals of internet and communication networks

2nd year
>MATHEMATICAL ANALYSIS 2 (FOR STUDENTS IN INFORMATION ENGINEERING)
>COMPUTER ARCHITECTURES AND OPERATING SYSTEMS
>LOGIC AND ALGEBRA
>ELECTROMAGNETICS AND FIELDS
>PROBABILITY AND STATISTICS FOR COMPUTER SCIENCE
>THEORY OF STOCHASTIC PROCESSES
>ALGORITHMS AND PRINCIPLES OF COMPUTER SCIENCE
>SIGNALS AND SYSTEMS FOR COMMUNICATIONS
>FUNDAMENTALS OF AUTOMATIC CONTROL

3rd year depends mostly on the courses you choose to take from a list.

[Anonymous No.15053404]

>>15053391
yeah, that look more like CS than CE. you'd want to look for courses like HDL design, VLSI design, microprocessors, embedded systems. although for what its worth, you can self study of lot of this. buy a $10 STM chip, slap it on a board, download the 1600 page manual, and go wild.

[Anonymous No.15053456]

what generals does /sci/ need?

[Anonymous No.15053487]

>>15053456
It already has all the ones it needs except maybe a physics general. But whenever someone starts one it gets spammed by trolls and schizos and quickly dies.

[Anonymous No.15053500]

What is the best math flowchart?
Also how do I become a god at DiffyQs?

[Anonymous No.15053502]

biology/nutrient question

I have a really hard time finding data related to "nutrient longevity". I am trying to figure out what foods are worth to mealprep/cook ahead of time and how long I can store it before it just turns into a waste basically.
is there a way to conveniently look this stuff up?
should I even be worried about this?
should I just look up the half life of the given vitamins for example?

qrd: How much nutrients do certain foods lose when meal prepped?

[Anonymous No.15053555]

how can I show by induction that [eqn]n!\geq4^n \hspace{.2cm} \forall n\geq9[/eqn]

[Anonymous No.15053564]

>>15053500
>the best math flowchart?
the one you make yourself. Get a few books on each topic. Start reading the first 10 or so pages in each and continue with which one you like the most.

[Anonymous No.15053570]

>>15053555
[math] \displaystyle
n! \geq 4^n \\
n! \cdot (n+1) \geq 4^n \cdot 4 \\
(n+1)! \geq 4^{(n+1)}
[/math]

[Anonymous No.15053586]

>>15053564
with basic calculus and proofs will I have enough to do that?

[Anonymous No.15053587]

>>15053555
Show it's true for n=9 and then for n+1 (hint: use the given assumption)

[Anonymous No.15053593]

>>15053586
depends on the book, obviously. list the topics you know and the topics you want to know and we'll tell you which you can tackle.
also, most books will list the assumed knowledge in the foreword.

[Anonymous No.15053606]

>>15053570
>[math]n! \cdot (n+1) \geq 4^n \cdot 4[/math]
I don't get this step
>>15053587
I know, but how exactly? I'm having a hard time showing it's true for n+1

[Anonymous No.15053614]

>>15053606
>I don't get this step
you multiply these two equations together
[math] \displaystyle
n! \geq 4^n \\
n + 1 \geq 4
[/math]
the first equation is assumed to be true (thats how induction works), and the second equation follows from [math] n \geq 9 [/math].

[Anonymous No.15053621]

>>15053606
I'm too lazy to do write it out properly but
n! * (n+1) > n! * 4 (since n > 9)
n! * 4 > 4^n * 4 (because of the base case)

does that help? inequalities can be tricky to understand

[Anonymous No.15053630]

>>15053614
oh, I get it now. but to assume that [math] n+1 \geq 4 [/math] shouldn't you prove the base case for n = 4 instead of n = 9?
>>15053621
I tried doing this, but I got nowhere

[Anonymous No.15053633]

>>15053630
n = 3 *

[Anonymous No.15053635]

>>15053360
>not sure why this is in physics
Exactly two reasons:
>I didn't know where to put it
>I didn't want to create an engineering tag to misclassify it

Also cute Satoko.

[Anonymous No.15053643]

>>15053630
>I tried doing this, but I got nowhere
what do you mean? it's literally solved

[Anonymous No.15053649]

>>15053614
i couldve explained this better.
you know how you can take an equation like [math]y^2 = x^3 + 6x + 9 [/math] and multiply both side by [math] 2 [/math] to get [math]2y^2 + 2x^3 + 12x + 18 [/math]? think of that like multiplying the two following equations together:
[eqn]
2 = 2 \\
y^2 = x^3 + 6x + 9
[/eqn]
(someone please tell me how to align equations in mathjax)
when you're dealing with inequalities, you open open your options for what you can multiply/add to the equations. you could, say, add 5 to one side and -3 to the other, as long as it preserves the inequality.
>>15053630
>but to assume that [math] n+1 \geq 4 [/math] shouldn't you prove the base case for n = 4 instead of n = 9?
[math] n+1 \geq 4 [/math] obviously starts working at n = 3, but we're only interested in n geq 9 because thats where the basis becomes true.
>>15053635
>Also cute Satoko.
ty <3 theres like zero new satoko art so im going back and picking out some favorites from my folder

[Anonymous No.15053654]

>>15053643
how is it solved? you just showed that
[eqn] n\cdot(n-1)\cdot ...\cdot 4^2 \cdot 3 \cdot 2 \geq 4^{n+1} [/eqn]
>>15053649
>but we're only interested in n geq 9 because thats where the basis becomes true.
but you stated that [math]n\geq3[/math]

[Anonymous No.15053659]

>>15053654
[math]n \geq 9[/math] implies [math]n \geq 3[/math].

[Anonymous No.15053667]

>>15053659
wouldn't it imply only that [math] n > 3 [/math] ?

[Anonymous No.15053670]

>>15053667
[math]n > 3[/math] implies [math]n \geq 3[/math].

[Anonymous No.15053673]

>>15053670
but how? I honestly don't get it

[Anonymous No.15053681]

>>15053673
the statement "2 = 2 or i am god" is a true statement, even if the second condition is definitely false. similarly, if [math] n > 3 [/math] is true, then [math] n > 3 \lor n = 3[/math] must also be true.
you said "wouldn't it imply *only* that...", but my statement was more general than yours.

[Anonymous No.15053685]

>>15053681
I think I get it now. thank you for being patient with me anon, I just so happens that I'm not very smart

[Anonymous No.15053693]

>>15053404
those are all courses i have in my bachelor or will have in my EE master, so im hoping i made the right choice

[Anonymous No.15053696]

>>15053502
bump?

[Anonymous No.15053703]

is there a simple way to reuse equations with sympy?
like start with x - y
then subs x and y both with the constant motion equation but give both the symbols separate/unique symbols
then use simplify or solve for t
if I just substitute, then it ends up with nothing because every term cancels out

[Anonymous No.15053709]

>>15053685
fyi this has nothing to do with the original question. let me try to explain it better:
we are trying to prove that [math]n! \geq 4^n[/math] for [math]n \geq 9[/math]. we know just by calculating that [math]9! \geq 4^9 [/math], so we only need to show that [math]n! \geq 4^n[/math] implies [math](n+1)! \geq 4^{(n+1)}[/math] to finish the proof, and we still get to assume that [math]n \geq 9[/math]. we will begin by assuming that [math]n! \geq 4^n[/math] is true, and we'll try to algebraically manipulate it into [math](n+1)! \geq 4^{(n+1)}[/math]. we can do this by multiplying the left side by [math]n+1[/math] and the right side by [math]4[/math]. are we allowed to do this? well, we know that [math]n+1[/math] is definitely bigger than [math]4[/math], since [math]n \geq 9[/math], so doing this will preserve the inequality. we thus prove the inductive step and conclude the proof.
>>15053404
well best of luck to you fren. try to take a computer architecture course if you can.

[Anonymous No.15053718]

>>15053709
it all makes sense now. thanks anon

[Anonymous No.15053724]

>>15053718
anytime fren <3
>>15053693
>well best of luck to you fren. try to take a computer architecture course if you can.
meant to say operating systems actually. youll pick up comp arch just through exposure.

[Anonymous No.15053737]

>>15052868
What IS the Big O of f? Don't tell me the exact definition, just tell me the intuition behind it.

[Anonymous No.15053743]

>>15045395
flip the diagram and think of it as [math]k(\omega) [/math], then there is no valid wavevector for [math]\omega < \omega_p [/math] because it isn't in the function's domain
have you gone through the derivation in a textbook (e.g. Chapter 14 of Kittel's Solid State Physics)?

>>15053703
assign x - y to a variable or to an equation object, works for me, something like
f = Eq(x - y, 0)
f.subs(x, t**2).subs(y, 2*t).simplify()

[Anonymous No.15053759]

>>15053737
consider two functions of x, f(x) and g(x), and define q(x) = f(x) / g(x)

when x goes to infinity, there are three possibilities, either q(x) goes to 0, q(x) approaches a non-zero limit L, or q(x) approaches +/- infinity.

only in the second case do we consider f(x) and g(x) of the same "class", they grow in a similar way for large x. only in the second case does f(x) = O(g(x)) and g(x) = O(f(x))

[Anonymous No.15053764]

>>15053759
in short, the notation is used to represent the class to which a function belongs, these classes consisting of all the functions which can be said to behave similarly as x grows large

[Anonymous No.15053773]

>>15053737
It's a classification of how f(n) scales for very high n.
Typically f(n) is the number of steps in algorithm and n is the size of the input.
The point of big O is that you group similar f(n) depending on their behavior at n going to infinity, and you ignore constant factors and non-leading terms because you care only about the big picture
So if f(n) = 3 log n + 4, you're like OK, scales logarithmically in n so it's O(log n), or if f(n) = 0.5n^2 + 5n + 20, it scales quadratically, so it's O(n^2)
Often you compare big O scalings of different approaches, so for example for n by n matrix multiplication the simple algorithm is O(n^3), but there is a faster algorithm which is O(n^2.807), or for sorting a list of length N, a dumb algorithm will be O(N^2), but a good one will be O(N log N)
It's also often used in physics to write high-order terms in series expansion (that then get ignored), so stuff like sin x = x + x^3/3 + O(x^5) indicating that the error in the approximation scales that way, you do some math and as long as the result has a higher order term you can ignore it

[Anonymous No.15053791]

>>15053737
math:
if [math]O(f) > O(g)[/math], then f "totally mogs" g. that is, the ratio [math]\frac{f}{g}[/math] goes to infinity as you get farther out. g can never hope to compete with f.

cs:
if an algorithm is [math]O(n)[/math], and it takes an hour to run it for an input of size 100, then you can *maybe* expect that it would take 2 hours to run it for input of size 200. if its [math]O(n^2)[/math], then doubling the input size might result in a runtime of 2^2=4 hours.

[Anonymous No.15053808]

>I got rangebanned sometime between making this thread and now
Legitimately wondering if the mods are constantly warning and banning me but I never see it because my browser cleans cookies after I close it and my IP resets on its own more often than I thought or if I live next to a tremendous shitposter.

[Anonymous No.15053811]

>>15052899
What exactly happens when an antenna receives a radio signal? Does the EM radiation from a transmitter set up an electric field between the antennas, which in turn creates a current in the receiver circuit?

Needless to say, I did't do too well in electromagnetism :(

[Anonymous No.15053820]

can someone explain what a transistor does and why they are necessary?
t. fresh csfag

[Anonymous No.15053821]

>>15053593
I know calculus up to three variables, triple integrals and all that bullshit
I'm a little rusty since that was like three years ago
I know basic elementary linear algebra and also basic ODEs
then I got thrown out of uni for rebuking a teacher regarding religious stuff, but anyways...
I want to be become a god at diffyQs
so everything diffy Q
and also fourier stuff
I see the world and I see a diffyQ

[Anonymous No.15053837]

>>15053821
>diffyQ
>fourier
cant rec this book enough, chapter 2 or 3 he derives fourier transforms the way that fourier himself did, in the context of heat flow.

[Anonymous No.15053919]

>>15053820
a transistor can be thought of as a resistor whose value is controlled by a voltage. so theres three terminals, and the terminal that controls the resistance is called the gate (im gonna talk about MOSFETs), and current flows between in the other two terminals called the drain and source. in an NMOS, for example, the resistance between the drain and source is high if the voltage at the gate is low, and the resistance is low if the gate it high. im skipping over a bunch of details, but the NMOS can be thought of as an AND gate. say we're measuring the voltage at the source. the voltage is only high if both the gate AND drain voltages are high. this is how we make solid state machines that can perform logic.

[Anonymous No.15053926]

>>15053808
based 2hu nigger
t.electrical engineering undergrad lurking this thread

[Anonymous No.15053967]

>>15053362
cs is called informatics in evrope

[Anonymous No.15054007]

>>15053919
ugh, that's a bit rough for me
I am not great at physics (for now atleast), could you dumb down the physics aspect as much as possible?
what would happen if you tried to make a computer without transistors?
in a sense it helps you "break up" a circuit into smaller ones that are "less dependant" on each other? is that kind of it or am I completely wrong?

[Anonymous No.15054026]

>>15054007
watch this video and then reread my post
https://youtube.com/watch?v=lNuPy-r1GuQ

[Anonymous No.15054063]

>>15054007
Not >>15053919, but you cannot build a computer (at least one as we know it) without transistors. Transistors are essential, and their invention revolutionised the electronics industry. Before transistors there were vacuum tubes which had a similar functionality, but transistors can be made microscopically tiny. Billions of transistors can fit into the area taken up by one vacuum tube.

Think of a transistor as a three-terminal component. A transistor can either work as a switch or as an amplifier.

As a switch, a transistor will only allow current to pass trough two of its terminals if there is current going through the third terminal. If there is no current at that third terminal, the transistor will "block" all current that attempts to go through one of the other terminals (keep in mind that the terminals on a transistor are not arbitrary, but I'm dumbing things down here).

This property allows us to construct digital circuits, consisting of gates such as AND or NOT. These gates are the building blocks of digital electronics, including circuits such as processors.

[Anonymous No.15054078]

>>15054063
Meant to write that there has to be a voltage on that third terminal in order to allow current to flow, not current. Whoops.

[Anonymous No.15054144]

>>15053696
A chemist can weigh in on this, but your answer is quite dependent on which nutrients your looking at, the meal itself, how you cooked it, and how you stored it (just to name a few). I mean you can look at the Gibbs free energy to get a sense of general reactivity if you knew the chemicals your interested in, but that's not really enough to say if meal A breaks down quicker than meal B.

[Anonymous No.15054153]

why are trannies so deranged

[Anonymous No.15054163]

>>15054026
>>15054063
>>15054078
thanks, I think I'm starting to get it.
I need to digest it but I'm starting to understand

[Anonymous No.15054174]

>>15053811
Electric field moves charges in a conductor; moving charges are current and separated charges have a voltage between them

[Anonymous No.15054272]

>>15054153
tautology

[Anonymous No.15054316]

>>15053820
Transistors are amplifiers. Both types (bipolar and FET) limit the flow of current based upon an input current (bipolar) or voltage (FET). In digital logic, they're used like switches; either the current is limited to a negligible level (off state) or the limit is higher than the current you would actually try to pass through it (on state). They can be combined to build logic gates, which in turn can be combined to build digital circuits of arbitrary complexity (modern CPUs have over a billion gates).

You could build a computer using valves (tubes), and that's how the earliest ones were built. But valves are huge, draw a lot of current and generate heat; transistors are tiny, a few nanometres across. The size of valves would limit the speed of a circuit simply because of distance and the speed of light. You could even build a computer using electromechanical relays, but that would be insanely slow (the clock speed would probably be less than 100 Hz) and unreliable (mechanical contacts wear out).

[Anonymous No.15054339]

/ck/ here. saturated fats are supposed to be more chemically stable than unsaturated fats right? why then does butter have a lower smoke point than things like corn or vegetable oil?

[Anonymous No.15054433]

>>15053808
Nvm I'm retarded.
>>15053926
Thank you for the kind words.

[Anonymous No.15054445]

If I played 36 games of roulette, each making a bet of the same amount on a single number with a 1:36 payout, what are my chances of winning?

[Anonymous No.15054470]

>>15052868
need a reason why i shouldnt end myself

also if i cut my wrists and put them in warm water, will it numb the pain?

[Anonymous No.15054474]

>>15054470
>>>/adv/

[Anonymous No.15054527]

>>15054445
Define "win".
Get at least two wins (and, hence, profit)?
Use the properties for the Bernoulli to calculate the probabilities of getting 0 or 1 successes and then subtract that from 1.

[Anonymous No.15054565]

smoked another cigarette. didnt really like this one.
how many cigarettes have you smoked?

[Anonymous No.15054685]

I want to prepare for my linear algebra class next semester. I know math up to differentiation (forgot the rest of calc).
Should I jump into linear algebra with Strang's LA book?
Or should I learn discrete math, or something else first?
Need advice

[Anonymous No.15054691]

>>15054685
3b1b series

[Anonymous No.15054703]

>>15054685
strang is shit. use axler if you want a rigorous approach, or lay if you are an engineering student

[Anonymous No.15054834]

>>15053391
don't you have calculus>

[Anonymous No.15054843]

>>15054703
I'm doing CS.
>>15054691
Thanks. Going to start this first.

[Anonymous No.15054916]

>>15054470
learn math.
You have embraced satan by leading a hedonistic lifestyle. God will accept you and show you the way when you try to solve his puzzles and grow closer to him.
Let your very existence be an act of defiance against the satanic culture into which you were born.

[Anonymous No.15054925]

Are Norman Wildberger's videos good for learning math, or are they just memeshit?

[Anonymous No.15054956]

>>15054916
>hedonistic lifestyle

i dont live a hedonistic lifestyle. I dont drink,smoke or party. I prefer a solitary lifestyle and unfortunately that doesnt mesh well with most people

>learn math
im fortunate enough to know enough math to have been accepted into an engineering school

>God
im an atheist

>your very existence be an act of defiance against the satanic culture

camus's philosophy of accepting the absurd is appealing to me but im not strong enough

[Anonymous No.15055063]

>>15052868
Can you fegs pls help me, I still have one hour:
If you have an animal with a small surface area, is there a limit to which it'll take no damage from a fall?

Has to do with drag.

In general, bigger surface area => slower fall. So I assume the answer is:
"No, a smaller surface area decreases drag. It is a light mass that affects how hard an animal will hit the ground, in combination with a bigger surface area."

Sounds good or am I being a retard?

[Anonymous No.15055065]

>>15055063
Phrased that like a retard, the question asks:
>Is there a surface area A, where an animal will never die from a free fall?

[Anonymous No.15055107]

why does y get the absolute value sign and x dont?

[Anonymous No.15055109]

>>15054956
>I dont drink,smoke or party
But you watch anime, porn, and play video games all day.

[Anonymous No.15055110]

>>15055107
Why do you think anon? I suggest looking at it before asking.

[Anonymous No.15055112]

>>15055107
also, +c isnt a part of the ln stuff, like its seperate... why does it get e'd? wouldnt it be e^ln + e^c ???

[Anonymous No.15055114]

>>15055112
Why do you think anon? I suggest looking at it before asking.

[Anonymous No.15055121]

>>15055110
>>15055114
i hope you trip and fall into a volcano

[Anonymous No.15055139]

>>15053837
The most natural way I've seen is to take a function, f(x), then generate in a natural way the periodic function:
F(x) = ... + f(x-2L) + f(x-L) + f(x) + f(x+L) + f(x+2L) + ...
Computing the fourier series coefficients of F amounts to computing the fourier transform of f at integer multiples of 1/L.
Basically, starting with Fourier series and a natural way of creating a periodic function from arbitrary f gives Poisson summation and a concrete meaning to what a fourier transform is.

[Anonymous No.15055149]

>>15055121
I won't because I fucking look at what I do unlike you.

[Anonymous No.15055240]

>>15054565
Zero.
Ciggies are the single stupidest way to get nicotine. Go vape or something.

[Anonymous No.15055258]

>>15055107
because x^2 is always positive

>>15055112
> +c isnt a part of the ln stuff,
there's a +C for both ln's but you can just combine them to make a single +C. same as the last step. e^C is just an arbitrary constant so you can just rename it C

> why does it get e'd?
because you are taking the exponent of both sides to remove the ln's

[Anonymous No.15055739]

>>15055240
ciggies are glamorous, remi

[Anonymous No.15055804]

Got absolutely railed on this question.. Where did I go wrong? Should I have rewritten then integrated w.r.t y?

How do I continue? Do I need to use properties of logarithms, or approximate with some power series? If there is a substitution that would help, I'm just not seeing it..

Not asking for a solution, but if anyone has any insight on how to proceed.

[Anonymous No.15055887]

>>15055739
There are cigars for that.

[Anonymous No.15055952]

are remiliaposter and satokoposter the same person

[Anonymous No.15056022]

>>15055804
I'd almost think there's a typo in that question since there is no simple closed formed solution to that integral. Do they expect you to use some kind of numerical approximation?

[Anonymous No.15056206]

This is true, right? [math]|f(x_n ) - f(x)|+|f(x) - f(x_m ) |\leq \sup_{x,x_n}|f(x)-f(x_n)| + \sup_{x,x_m}| f(x)-f(x_m)|[/math]

[Anonymous No.15056209]

How do I become smarter long-term? I am dumb and dyscalculic.

[Anonymous No.15056215]

>>15056022
Yeah Idk I give up, I hope there is a typo because I've wasted too much time..

[Anonymous No.15056255]

>>15056206
Yeah.

[Anonymous No.15056267]

>>15055952
Yes.

[Anonymous No.15056283]

>>15055887
>that remi
theres something so wrong with a girl smoking a cigar.
cigarettes are way cooler than cigars, cigars fall into that same category of soi that beer, beards, axe throwing, and other stereotypical masculine stuff sometimes falls into. its very gay and very unbased. and cigars are probably worse for you than cigarettes.

[Anonymous No.15056300]

Can anyone provide a list of first and second year chemistry bachelors books ? For a fag who don't know anything about chem ?

[Anonymous No.15056323]

>>15056283
>soi
No.
>beer
Literally nothing wrong with beer.
>cigars are probably worse for you than cigarettes
They're better for your lungs since you aren't supposed to actually inhale the smoke.

[Anonymous No.15056337]

I face a lot of problem while reading stuff these days, I don't know why but being an engineering student I literally ready everything so deeply and my brain try to analyse each and every word like I am reading a test paper. I don't face a lot of problem doing maths and physics but whenever ever a question with bizzare English pops up it makes me very :(
Pls help anons it makes me overthink a looottttttt

[Anonymous No.15056420]

0.75 has an r, not an s. why is 0.75 on the s side???

[Anonymous No.15056435]

>>15056420
the problem after that was dr/ds = 0.75s and that comes out to r=0.375s^2 +c which makes sense... but the previous one had an r which was also connected to r

[Anonymous No.15056462]

>>15056420
>why is 0.75 on the s side???
for the same reason it is 1/r on the dr side, a rearranging of the variables. (multiply both sides by ds / r)

[Anonymous No.15056504]

>>15052868
How should I interpret V in volume integrals for example.
[math] {\displaystyle \int_V dV = \int_0^{2\pi}\int_0^{2\pi}\int_0^{2\pi}dxdydz } [/math]
I've always just ignored the V and assumed it to be a shorthand for my bounds, but can you formally use it to show what you're integrating over? Can anyone explain what it means and what the formalisms are when using them?

[Anonymous No.15056513]

>>15056504
> How should I interpret V in volume integrals
As the volume. Everything else is just a way to describe that volume in a particular coordinate system.

[Anonymous No.15056525]

>>15055109
>anime

i dont watch anime anymore. Nothing made today will have the same maturity as legend of galactic heroes(1988 )
>porn

not a porn addict.

>video games
only play after completing my school work as way to relax and as a reward

[Anonymous No.15056802]

>>15056525
> Nothing made today will have the same maturity as legend of galactic heroes(1988 )
based.

How old are you? Why do you want to an hero?

[Anonymous No.15056836]

>>15052868
Would learning set theory before combinatorics make it easier?

[Anonymous No.15056981]

>>15052868
Former polsci student here. How do i get into financial math? I want to work as an actuary some day.

[Anonymous No.15056985]

When a wavefunction collapses after being observed, does it remain collapsed forever or does it return to being a gay probability again immediately after the instance it is observed?

[Anonymous No.15057008]

>>15056981
Financefags don't use any advanced math. Just brush up on high school-level math (algebra, calculus, a bit of statistics and probability) and read some economics textbooks. Along the way, it might help to learn one programming language to make scripts that'll automate various data filtering and processing tasks.
Contrary to what people meme about, you don't need an extremely advanced knowledge of math or AI to do actuarial work. You just need strong basic math fundamentals and an ability to associate various topics in microeconomics, finance, and risk-taking to numerical data.

[Anonymous No.15057032]

>>15056836
you need to know the absolute most basic notation of set theory, but anything beyond that probably isnt gonna make it easier.
>>15056985
the wave function never really stops being a probability. you can collapse it down to basically a delta function but never to an exact point. and even if you could collapse it to one point itd still technically be a probability, just that 100% of the probability distribution is located at one point.
and yes, as soon as youre done measuring the particle or whatever, the wave function begins to "widen" over time as per the schrodinger equation.

[Anonymous No.15057046]

>>15057008
That's helpful. Thanks

[Anonymous No.15057085]

How come there is pseudoscience but not superscience?

[Anonymous No.15057090]

>>15056504
It is the set of points you are integrating over.

[Anonymous No.15057095]

>>15057032
Thats interesting although i dont understand it completely since im a mathlet. Im assuming that means shrodingers dead cat slowly returns into a superposition again after its confirmed to be dead and can become alive again after a subsequent recollapse meaning zombie cat! I wonder what determines how long it takes for the wave function to widen, obviously it doesnt return to 50/50 immediately after you confirm it to be dead
Tank u for the answer

[Anonymous No.15057108]

>>15057095
>Im assuming that means shrodingers dead cat slowly returns into a superposition again after its confirmed to be dead and can become alive again after a subsequent recollapse meaning zombie cat!
very cute

[Anonymous No.15057123]

If a language is in P, can I say it is pspace complete?

[Anonymous No.15057183]

Someone recommend Professor Leonard for math videos and his vids are helping me a lot. Thanks.

[Anonymous No.15057250]

Are there any non-codemonkey programming language books that builds the language from ground up. Something that clearly says what each symbol in the code does, and how it does it, instead of asking you to just load these packages and use these functions to do this. Something like a math textbook, that builds the definitions and theorems from Set theory.

[Anonymous No.15057319]

Do you guys know of any book/free course that I can find online on electronics? I want to build simple stuff at home but I need a guide that really spoonfeeds me as I've never done anything like this before. I've classical understanding of electromagnetism but other than that I've no clue in the field.

[Anonymous No.15057470]

Bros, does anyone in a difficult major like EE or Physics have enough time to learn some other skills? I was planning to teach myself different parts of robotics since my uni courses on robotics aren't very good.
Unfortunately, not only do I have very little time to devote to it, my uni has shifted from a 4 month semester to a 6 month semester. Idk if thats good or bad but they'll be increasing all the syllabuses and that means more study.

[Anonymous No.15057477]

>>15057123
No. Those are two very different complexity classes.

[Anonymous No.15057478]

>>15057470
>a 4 month semester
Isn't that called a quadrimester?
You do know that the "se-" in "semester" means "six" and the "-mester" means "month", right?

[Anonymous No.15057504]

>>15057478
oh yeah sorry. we call them all semesters.

[Anonymous No.15057511]

>>15057477
I'm trying to prove this is complete under of the complexity classes.

[Anonymous No.15057586]

Say I have 40 baskets, each baskets has 0, 1 or 2 pieces of fruit. How could you tell how many pieces of fruit are in each basket knowing only the weights of the baskets?

My method is
>Ignore baskets with weight equal to 0
>Sum all weights and divide by the number of non-empty baskets to get the average weight of each fruit-containing basket.
>Use the average weight of each fruit-containing basket to make an approximation of how many fruits are in each basket (basically round to the nearest integer)
>Use the approximation of how many fruits are in each basket to calculate the average weight of an individual piece of fruit
>Calculate the number of fruits per basket dividing each basket's weigh by the average weight of an individual piece of fruit.
>Iterate again just in case

Is this retarded? Is there a better way?

[Anonymous No.15057591]

>>15052868
Why is pushing a car from the front harder than pushing it from the back? Is it something to do with the orientation of the wheels?

[Anonymous No.15057606]

>>15057591
Wut? A car has the same resistance to being moved wether you push it forward or backwards.
Maybe you feel that way because since the front is lower than the back you have a more awkward posture when exerting the force, and more of it is lost to the vertical component.

[Anonymous No.15057621]

>>15057090
Alright, this is exactly what I was looking for. So can I write:
[math] V = \{(x, y, z) : 0 \leq x \leq 2 \pi, 0 \leq x \leq 2 \pi, 0 \leq y \leq 2 \pi, \} [/math]?

[Anonymous No.15057624]

>>15057621
Fucked up a bit copy pasting, there should be no comma at the end and should be variables x, y, z instead of x, x, y.

[Anonymous No.15057732]

>>15057621
Yes. The point of writing V is you do not assume any coordinate system as opposite to triple integral which assumes cartesian. Also the correct notation for volume is:
[eqn] \int_S f \mathrm d V [/eqn]
where [math] S [/math] is the set of points and [math] \mathrm d V = \mathrm dx \mathrm dy \mathrm dz [/math] is a tiny volume.

[Anonymous No.15057877]

>>15057250
https://mitp-content-server.mit.edu/books/content/sectbyfn/books_pres_0/6515/sicp.zip/index.html

[Anonymous No.15057907]

how do i program modulo operation with repercusion?

[Anonymous No.15058126]

>>15057907
repercusion?? do you mean recursion?

[Anonymous No.15058152]

>>15057732
I got it then, tenks man.

[Anonymous No.15058200]

>>15052868
How would I go about writing an arbitrary [math]\sigma \in S_n[/math] in cycle notation as a product of disjoint cycles? My idea would be to notate it as something like [math]\sigma = (k_{11}...k_{1n_1})(k_{21}...k_{2n_2})...(k_{m1}...k_{mn_n})[/math] but that seems clunky and stupid and difficult to work with. Isn't there a better way? For context I'm trying to make conclusions about the cycle structure of [math]\sigma[/math]

[Anonymous No.15058256]

>>15057586
Sum the weights of all baskets.
This must equal the sum of the weights of all fruits (trivially), so we just divide it by 40 to get the individual fruit weight.

[Anonymous No.15058308]

>>15058256

[Anonymous No.15058397]

Without resorting to trigonometric functions, what's the easiest (elementary, geometric) way to see that [math]B/A = B'/A'[/math]?

[Anonymous No.15058456]

>>15053502
This sounds like an extraordinarily retarded thing to worry about. Just eat a varied diet.

[Anonymous No.15058607]

>>15058397
aas congruence with [math]\alpha , 90, 1[/math]

[Anonymous No.15058612]

>>15058607
it's a similarity not a congruence tard. AAA implies similar.

[Anonymous No.15058642]

>>15058612
rescale them so they both have the same side of length 1

[Anonymous No.15058649]

>>15058397
https://mathcs.clarku.edu/%7Edjoyce/java/elements/bookVI/propVI4.html
>>15058607
>>15058642
you dont need a side to prove similarity if you already have two angles. "AAS" similarity isnt a thing.

[Anonymous No.15058651]

>>15058200
Why not [math]\sigma = \prod_i \sigma_i[/math] ?

[math]\sigma_i[/math] disjoint, cyclic

[Anonymous No.15058661]

>>15058649
I never really did euclid so I don't know our axioms and operations here but is there really a difference between similarity and congruence modulo scale?

[Anonymous No.15058672]

>>15058661
iunno i just googled "proof that similar triangles have proportional sides" and thats what came up. desu i cant really follow it.

[Anonymous No.15058982]

How does z-transforming problem (b) work?

I got the first one cause it was easy but I'm not sure how to approach the 2nd.

If x[n] = u[n], then does x[n-1] = u[n-1]?

[Anonymous No.15059047]

>>15058982
>If x[n] = u[n], then does x[n-1] = u[n-1]?
yea

[Anonymous No.15059048]

>>15059047
AH-- then I can just use the difference formula!
Solved!

Thanks senpai!

[Anonymous No.15059050]

>>15059048
np fren <3
i hope youre not the same guy from like two years ago that was having trouble with control theory.

[Anonymous No.15059054]

>>15057319
I'd suggest you to sign up for a community college or trade school course on soldering. You can learn about circuit design and all using simulators, but if you really wanna assemble circuits for testing, you should find somebody who can teach you the proper rules of it so you learn how to cut wires and solder and unsolder stuff without burning yourself or wasting an entire roll of soldering tin. If you can make a good friend or an older, but extremely patient family member help you with it, then do it.
Other than that, I guess you can read Owen Bishop's Electronics: A First Course and start out by building various easy projects available on Instructables.
Some of the first stuff you should make should be stuff that you know for certain ought to work if done correctly, like a circuit that just lights up one LED light. Then you can start incorporating resistors and capacitors to modulate frequency, inductors to either expand or minimize electromagnetic fields, transistors to work as analog conditional gates, and ICs to split up electromagnetic waves into several several pieces. Slowly work your way through building increasingly more complex circuits that can control signals and use them to power up different things, like a series of lights, a tiny solenoid engine, a wave frequency modulator, and buzzers.
For inspiration, you can visit >>>/diy/ohm but I'd think it'd be best to try to reach for easy stuff and to really get a good grasp of the uses and capabilities of every single basic component in electronic circuits before you jump into really cool-looking stuff.

[Anonymous No.15059212]

Would you fuck yourself? I mean completly perfect clone.

[Anonymous No.15059291]

is wrong to look down on people who are athletes or people who build muscle because they could be shot in the head, rendering all the time they spent on their body useless

[Anonymous No.15059296]

>>15059212
no, not gay
>>15059291
well anyone could get shot in the head, and everyone will eventually die. what makes an athlete so special?

[Anonymous No.15059325]

>>15059050
Nah-- I'm not that anon. Haven't been on /sci/ that long (used to go to /wsr/ for these things but I've evolved past that point).

[Anonymous No.15059416]

Why is [math]2^X[/math] the largest algebra over [math]X[/math]?

[Anonymous No.15059429]

>>15058308
But what did you fix.

[Anonymous No.15059433]

>>15059416
What do you think?

[Anonymous No.15059454]

i feel worthless compared to you

[Anonymous No.15059466]

>>15052868
Good Morning /Sci/entists!

I am working on Kurumi MaidCard which is a Computer Program that can change text into a Maid Space and back. It is going to serve as a decentralized means of sharing books/Computer Program Code. A Maid Card is going to consist of a Maid Sticker and a drawing of a Maid Space.

The Maid Sticker is just supposed to be easily human readable/identifiable so you can tell which card you are using quickly. I got the idea from stickers on Super Nintendo games. Attached is an example. It is the Maid Sticker for Kurumi MaidCard.

The Maid Space itself holds the information because all the information there is, is just a number and Maid Space can count to any number except God.

I will put an example showing this in my next post.

I put the KJV Bible in a Maid Space. The conversion worked, but the problem is the PNG of the Maid Space (without even adding the Maid Sticker) is 8MB.

This isn't a huge problem, because 8MB isn't massive, but it is too big to post on 4Chan, without even adding the Bible's Maid Sticker. I would like to learn tricks from image compression to make it smaller.

The compressed image needs to be viewable by humans without decompressing or using any tools. I only want to compress the Maid Space and not the Maid Sticker on the Maid Card if possible.

Please tell me a math for it and not a library because I have to make this without 3rd party dependencies in core Java 18.

Thank you /sci/entists for reading my post.

[Anonymous No.15059473]

>>15059466
Here is some of the Maid Space for the KJV Bible along with the Bible's Maid Sticker.

I am going to go work on deserializing Maid Space back into text and also study tricks from version control systems. I will return later to see what the /sci/entists had to say.

I am also open to making Maid Cards for other books if a Maid Sticker and the text of the book is provided, and the book doesn't have problems from copyrights.

[Anonymous No.15059546]

>>15059473
That's the most interesting version of the bible I've
seen since the version on microfiche.

[Anonymous No.15059573]

>>15059296
The time they spend on their bodies could be better used to help people or push humanity forward through scientific progress

[Anonymous No.15059579]

>>15059433
stop trolling

[Anonymous No.15059899]

>>15059429
i moved the mouth down a tad, original was giving me down syndrome vibes.
>>15059573
everyone has different ideas of what their purpose on this earth is. helping people may be considered admirable, but the fact is that there are very few people that spend a significant amount of their time helping others. if you really wanted to rationalize things, you could argue that athletes do help people by participating in publicized sports that bring a lot of people a lot of happiness, but perhaps not you. maybe the weightlifter at the gym has a wife thats really happy seeing her husband in good shape. maybe an obese person on the brink of cardiac arrest was finally motivated to lose weight after seeing so many fit people, and he was able to live long enough to see his children grow up. maybe one of the children becomes a world renowned biologist. maybe he genetically engineers crops that completely eradicate world hunger. not everyone should have a world-on-your-shoulders mentality. whats the point of making progress if our posterity are slaves to their next generation? focus on you, and be a good person yourself. if you still have some time left over, then be a good husband and father. if theres time left still, be a good friend to those around you. be a hero to the few that you love. this has a bigger impact on the future than you may realize.

[Anonymous No.15060095]

>>15059899
This is a good answer, thank you.

I guess I'm just an alien compared to most human beings. I've never looked at another person and have ever been inspired. Ever since I was a kid Ive always thought that I should follow my own tune instead of relying on others for motivation/inspiration.

[Anonymous No.15060099]

how much is 5 + 5 - 5 * 5 / 5?

[Anonymous No.15060204]

>>15057586
Do you also know the weight of a fruit? Otherwise you cannot distinguish e.g. every basket containing 1 piece vs 2 pieces.

[Anonymous No.15060209]

>>15060099
5

[Anonymous No.15060251]

is it possible to make my dick smaller

[Anonymous No.15060285]

what are the major differences in photosynthesis between moss and plants, if any? i know mosses are non-vascular, and it seems like that would just kinda screw up the whole process

[Anonymous No.15060309]

>>15060099
5

[Anonymous No.15060323]

>>15060204
The fruits all have different weights. A strawberry weighs less than a pineapple for example.

[Anonymous No.15060343]

When picking your electives for college, do you go for something that is easy or something that is interesting to you?
I feel like taking something that is interesting, but I could easily study that in my spare time anyway. So what speaks taking the easiest class and securing an easy A?

[Anonymous No.15060346]

>>15060343
If it's so interesting, and you even want to study it in your spare time, why couldn't you get an A on a tougher subject?

[Anonymous No.15060368]

>>15060346
i made the mistake once that i underestimated the complexity of a subject, because the theoretical concepts behind it were very hard, even though i understood the practical application.

[Anonymous No.15060374]

>>15060368
to me that sounds like a good course to take, because you could learn something from it

[Anonymous No.15060380]

>>15060374
that's a good way of thinking about it :)

[Anonymous No.15060382]

whats the basis for people thinking that there even needs to be a graviton in the first place

[Anonymous No.15060465]

>>15059466
If you want a general lossless compression then use lempel ziv: https://www.youtube.com/watch?v=RV5aUr8sZD0
For non-lossless image compression use jpegs: https://www.youtube.com/watch?v=Kv1Hiv3ox8I

[Anonymous No.15060648]

>>15060382
Because the other three forces are described by quantum field theory and that states there must exist associated force carrying boson particle(s) (photons, W & Z, and gluons). Since General Relativity is also a (classical) field theory then once it's quantized it should also have a force carrier with certain properties, and that is the graviton.

[Anonymous No.15060904]

How do I find x when A isn't diagonalizable?

I already got the matrices for the SVD matrix but I'm not sure how to approach finding Ax = b here.

[Anonymous No.15061146]

>>15060904
from wikipedia, and apparently the pseudoinverse of a matrix is equal to the actual inverse as long as its actually invertible

[Anonymous No.15061149]

>>15061146
Thanks, my good anon.

[Anonymous No.15061324]

>>15060251
Yes, keep it locked up in progressively smaller cages.

[Anonymous No.15061336]

Is there any proof that thin women can grow very large breasts? Like say G/H cup or above.

[Anonymous No.15061351]

Where does this argument fail for non-normal distributions?
Phi is CDF, phi is density.

[Anonymous No.15061496]

>>15060285
Mosses and other non-vascular plants differ from vascular plants in that they lack the specialized tissue and structures needed to transport water and nutrients throughout the plant.
This means that mosses must rely on diffusion to absorb water and nutrients from their environment, and they must also rely on diffusion to transport the products of photosynthesis throughout the plant.
Additionally, mosses lack the specialized structures (such as stomata) that vascular plants use to regulate the exchange of gases during photosynthesis. As a result, mosses are less efficient at photosynthesis than vascular plants.

>>15061336
No, there is no scientific proof that thin women can grow very large breasts.
Breast size is largely determined by genetics, and while some women may be able to increase their breast size through hormone therapy or other means, it is not possible to increase breast size beyond what is genetically predetermined.

[Anonymous No.15061563]

>>15061351
This works as long as the pdf is symmetric, no?

[Anonymous No.15061669]

Let me know if this is all correct:

1. a square matrix (or the linear transformation that that matrix represents) is said to be orthogonal if [math] A^{T}A=I_n [/math] (the identity matrix), this implies that the invert of this matrix = its transpose

2. an endomorphism is said to be diagonalizable if there is a base of this endomorphism made of only its eigenvectors, therefore its associated matrix is a diagonal matrix with the eigenvalues on the diagonal.
Also, a square matrix A is diagonalizable if and only if it's similar to a diagonal matrix. [math]D=S^{-1}AS[/math], where D is the diagonal matrix with the eigenvalues on the diagonal and S is an invertible matrix with the eigenvectors of A as its columns.

3. An endomorphism is orthogonally diagonalizable if there exists an orthonormal base (of the space the endomorphism is working in) made of its eigenvectors. So the same definition of a diagonalizable matrix except the eigenvectors also have to be orthogonal one another.

Also, an endomorphism is orthogonally diagonalizable if and only if it's symmetrical (by the spectral theorem)

can i make sense out of the spectral theorem intuitively or should i just learn the proof and definitions?

[Anonymous No.15061671]

>>15061669
>orthogonal one another
and have a norm of 1 ofc

[Anonymous No.15061750]

Why do products and pullbacks/fiber products coincide in the category of S-Schemes?

I do not get why if X -> S and Y -> S are S-Schemes then the product, let's call it X x Y is a pullback as well.

I am pretty sure that I have to use the property of S-Sch being a slice category namely Sch/S but in the slice category the objects are pairs (X,f) of morphisms f: X -> S from schemes to S and not the same objects as the schemes itself.

[Anonymous No.15061767]

Good Morning /Sci/entists!

>>15059466
>FILE DELETED
>mfw
Does anyone know why the image on this post got jannied? It was just the example Maid Sticker for Kurumi MaidCard. A nice dra/g/on on /wsr/ made it.

>>15059546
Thank you fren.

>>15060465
Thank you for telling me. I am going to make a lempel-zig-tohru that applies lempel-ziv to Coolkyousinnjya Maid Space.

Thank you /sci/entists for reading my post.

[Anonymous No.15061786]

>>15060323
You still cannot be sure, how would you distinguish two light fruits weighing 1 and 3 from a larger fruit weighing 4?

[Anonymous No.15061936]

>>15061669
>1.
Yes.
>2.
Yes.
>3.
Yes.
>Also, an endomorphism is orthogonally diagonalizable if and only if it's symmetrical (by the spectral theorem)
Kind of? That's for stuff over the reals. A matrix needs to be normal to be orthogonally diagonalizable over the complex numbers.
>can i make sense out of the spectral theorem intuitively or should i just learn the proof and definitions?
Learn the proof and definitions, it's hard to just up and understand it.
>>15061563
Sounds correct to me.

[Anonymous No.15061980]

>>15054339
Butter is filled with milk proteins and other junk.

[Anonymous No.15062057]

>>15056504
[math] dV [/math] is the volume form of your manifold.
>b-but what does that mean
Lets assume you are working in a space that LOOKS like euclidean space close up; we call this space a manifold. If we can do calculus on this manifold, we can define the vector space of tangent vectors at a point in the manifold (tangent space at a point). With this tangent space, we can construct a co-space (think co-vectors); these co-vectors can be used to construct a higher dimensional analog to vectors (think areas and volumes as opposed to lines for vectors) called differential forms. The highest dimensional differential form is called the volume form of the manifold. Now, if you translate any right hand throughout your manifold and it stays right handed, the manifold is called orientable. You can define a measure (how you do integration) on your manifold with the volume form.

There are many other interesting points about this construction, but I hope that was understandable.

[Anonymous No.15062153]

>>15052868
Are there rabbits on the dark side of the moon? What is NASA hiding from us?

[Anonymous No.15062231]

how do I become a genius at neural networks and all that AI stuff?
I got a 4.0 in calc 3, but I dropped out of uni because it was too expensive
but with all this cool AI stuff happening I want to understand it all
I'm also interested in stuff like automata, and procedural generation. and also data visualization too maybe
I have a very basic understanding of C++ which I taught myself through youtube.
and I've already read most of a discrete math book
counting was probably the most interesting part to me, but I feel like a lot of counting formula was shoved at me without much reasoning, in fact I had to deduce the combinations formula myself for it to make sense.
My favorite kinds of proofs are probably induction ones.
Graphs interested me a bit, but all the stuff about coloring graphs was kind of dull to me
Right now I am reading Vector Calculus, Linear Algebra and Differential Forms: A Unified Approach by Hubbard and Hubbard.
I kind of feel like I'm in the deep end though, not sure how to get to where I want. I'm looking for some information and advice.

[Anonymous No.15062307]

does anyone cite arxiv articles?

[Anonymous No.15062379]

How do you get the derivative of x(e)^x using the limit definition?

[Anonymous No.15062390]

>>15062379
L'Hopital

[Anonymous No.15062419]

>>15062379
[math] \displaystyle
\frac{d}{dx} \left( x e^x \right) = \lim_{\Delta x \to 0} \frac{(x + \Delta x) e^{(x + \Delta x)} - xe^x}{\Delta x} \\ \displaystyle
= \lim_{\Delta x \to 0} \frac{xe^{(x + \Delta x)} - xe^x}{\Delta x} + \lim_{\Delta x \to 0} \frac{\Delta x e^{(x + \Delta x)}}{\Delta x} \\ \displaystyle
\lim_{\Delta x \to 0} \frac{\Delta x e^{(x + \Delta x)}}{\Delta x} = e^x \\ \displaystyle
\lim_{\Delta x \to 0} \frac{xe^{(x + \Delta x)} - xe^x}{\Delta x} = x \left( \lim_{\Delta x \to 0} \frac{e^{(x + \Delta x)} - e^x}{\Delta x} \right) = x \frac{d}{dx} \left( e^x \right) = xe^x \\ \displaystyle
\frac{d}{dx} \left( x e^x \right) = e^x + xe^x
[/math]
>>15062390
circular

[Anonymous No.15062420]

>>15062231
If you have to ask it's already over.
4.0gpa doesn't ask such retarded questions

[Anonymous No.15062450]

Will it be easier for me to solve tough single-varible calc problems after learning multi-variable calc ?

[Anonymous No.15062502]

>>15062419
thanks a bunch anon!!

[Anonymous No.15062506]

>>15062450
no
>>15062502
np fren <3

[Anonymous No.15062509]

>>15062506
Then how I can I master single variable calc so that I can solve most of the problems ?

[Anonymous No.15062511]

>>15062509
keep practicing. most integrals are unsolvable anyway, its not a big deal if youre not that good at it.

[Anonymous No.15062530]

>>15054834
thats probably what "analysis" is. CS majors would never take the course known in the states as analysis.

[Anonymous No.15062657]

>>15062420
It's ok that you don't know, I don't know either that's why I'm asking
we all gonna make it brah, don't worry

[Anonymous No.15062665]

>>15062231
>>15062657
How about you just try to make something? Some Ai to play against you on your favourite board game or something. Learn fundamentals as you need them.
If not, learn probability/stats, then some stochastic optimization techniques, and you're already pretty good. Note that this maybe doesnt sound like a lot but can (should) take like 3 years of studying.

[Anonymous No.15062673]

>>15062665
Maybe I will pick up a probability book, I heard that counting is related to probability
I've always been more of a "I'd rather take a car apart than drive it" kind of person

[Anonymous No.15062677]

>>15062673
probabilitybook.com is my recommendation

[Anonymous No.15062839]

H1 and H2 are two affine subspaces of an Euclidean vector space (so retarded words to say a general line or plane or hyperplane or whatever).

is saying [math]H_1\bot H_2[/math] perfectly equivalent to saying that [math]H_1=(H_2)^{\bot}[/math]?

[Anonymous No.15062854]

Where does the 1 in the sum come from? I don't exactly have a geometric series background

[Anonymous No.15062862]

>>15062854
> I don't exactly have a geometric series background
Have you hit puberty yet?

Also you can google something so basic: https://en.wikipedia.org/wiki/Geometric_series#Coefficient_a

[Anonymous No.15062883]

>15062862
>Also you can google something so basic
you sound just like every mathemathician professor with 15+ years background in math expecting everybody to have the same knowledge
but to answer your question, I'm a 25 y/o dude doing master study AI with no previous background in any math and started to learn on my own. happy?

[Anonymous No.15062893]

>>15062883
a 25y/o doing a masters in AI you would expect to know how to use a computer to research a topic especially since you seem to know its a geometric series. asking on 4ch seems like an idiotic place to ask first.

[Anonymous No.15062904]

>>15062893
>since you seem to know its a geometric series
because unironically I asked chatGPT. I didn't know what the fuck it was. now this is a question I could ask chatGPT, but I can't show him the graph where there's no 1 anywhere, but is in sum. the test is in 2 days, and I got more mathy shit than just this

>asking on 4ch seems like an idiotic place to ask first.
this thread is called "stupid questions thread" isn't it you dimwit?
either way, you're an arrogant useless cunt

[Anonymous No.15062919]

>>15062904
> because unironically I asked chatGPT
unironically you're an idiot.

[Anonymous No.15062949]

>>15062839
I don't think so; any subset of the orthocomplement of [math]H_2[/math], say [math]H_1[/math], would be orthogonal to [math]H_2[/math], but this does not have to be equal to all of [math]H_2^\bot[/math].

[Anonymous No.15062950]

>>15062919
thank you for your delightful insight
now kys

[Anonymous No.15062996]

>>15062854
>>15062883
No offence anon but did you even go to school? Arithmetic and Geometric sums are essentially covered day 1 of grade 1.

[Anonymous No.15063006]

What are some books that are actually decent unlike the Anarchist Cookbook? Asking for legal reasons I want to make a cool science project minecraft etc

[Anonymous No.15063025]

>>15062996
no offense to you either, but isn't this thread called /sqt/? I don't know why you guys are baffling when I ask an actual "stupid" question.
I dont live in the US, we don't have the same system here. in my carreer, the mathiest thing I had was basic divison

anyway, pretend I never asked. dont know why this thread exists when stupid questions are told to "just fucking google it".

[Anonymous No.15063026]

if you want to explain briefly to a layperson what moissanite is while mentioning "silicon" and "carbon" separately and not just "silicon carbide", could you say that it's a chemical compound made up of silicon and carbon or should you say something different like the atoms form a crystal structure or something?

e.g.
>moissanite is a gemstone of silicon carbide (______ of silicon and carbon)

https://en.wikipedia.org/wiki/Moissanite
https://en.wikipedia.org/wiki/Silicon_carbide

[Anonymous No.15063033]

would it be fair to call it a "combination" of silicon and carbon as opposed to diamond being pure carbon?

[Anonymous No.15063042]

>>15063025
that guy is just a cunt, it happens

[Anonymous No.15063060]

or simply
>moissanite is a gemstone of silicon carbide (silicon and carbon)
idk?

[Anonymous No.15063077]

>>15062904
don't ask any complex equations or math from chatgpt because it's wrong very often
but for the basic stuff it's 99% correct

[Anonymous No.15063083]

>>15063042
desu I thought it was a shitpost, even the stupid questions posted here rarely can be answered with a simply google any retard can manage.

[Anonymous No.15063111]

scientifically speaking is it better to have an SO who
>shares your hobbies
>shares some of your hobbies
>shares none of your hobbies

[Anonymous No.15063117]

>>15063111
some

[Anonymous No.15063161]

When it comes to synthetic supplements and drugs, none of them are 100% pure. Do we know that these impurities are safe to injest? Does someone have to test all of the impurities that result from the synthesis and check they are not dangerous at the doses that will be in the drug/supplement? And also were can I find information regarding the what impurities will be in what products and how much of them there are?

[Anonymous No.15063207]

why does /diy/ have the electrical engineering general instead of /sci/

[Anonymous No.15063219]

>>15063207
/sci/ fears the engineer

[Anonymous No.15063226]

Does working at your university or at a national laboratory look better for grad school? I got an offer this summer at a national lab and I was wondering if any anons could speak on their experiences there. I would be doing some embedded systems work if that changes anything.

[Anonymous No.15063260]

>>15063207
most of EE isnt science nor math

[Anonymous No.15063292]

>>15063260
couldn't be more wrong

[Anonymous No.15063394]

how do i do x and # raised to fractions? like is what was the trick?

[Anonymous No.15063449]

>>15063292
engineering is not science. in school it feels like you do actual math and science, but MAYBE 1% of EE graduates go on to do real science. most go on to do embedded work, circuit design, VLSI if youre good, or power systems. not knocking any of those (except power, power is for losers), but none of it really belongs on /sci/. in contrast, control theory, electromagnetics, and solid-state physics all definitely belong on /sci/.
btw /diy/ohm/ is for idiots. those people cannot do a fucking circuits 1 problem. one of those faggots got belligerent at me simply for posting a solution to someones problem when everyone else couldnt solve it. maybe remi has the post saved. those morons would shit their pants at the mere sight of a real EE general.
>>15063394
[math] \displaystyle x^{\frac{a}{b}} = \sqrt[b]{x^a}
[/math]

[Anonymous No.15063453]

>>15063394
[eqn]\#^{\frac{3}{2}} = \frac{\#^{3+2}}{\#^{3-2}} = \frac{\#^{5}}{\#} = \#^4[/eqn] etc.

[Anonymous No.15063455]

>>15063453
lol

[Anonymous No.15063528]

if diaphragmatic breathing is so good for us why do we naturally breathe with our chests

[Anonymous No.15063675]

>>15063449
>>15063453
swag
thanks guys
young boy never broke again

[Anonymous No.15063707]

Let [math]\mathrm{ev}_x:f\mapsto f(x)[/math] be the evaluation map of [math]f\in\mathrm{Hom}(X,Y)[/math] at [math]x\in X[/math]. Why is [math]\mathrm{ev}_x^{-1}(y)[/math] the same size as [math]\mathrm{Hom}(X\setminus \{x\},Y)[/math] for every [math]y\in Y[/math]?

[Anonymous No.15063727]

For this q, can we proof by showing that both 0 and [math]\infty[/math] are additive identity for [math]\infty[/math]. Which would mean there are two zero vectors. Since that's not possible R does not form a vector space over itself

[Anonymous No.15063732]

Let [math]\mathcal{F}[/math] be a family of sets. That condition could be expressed as [math]\bigcup \bigcup \mathcal{F}\neq \bigcup \mathcal{F}[/math], right?

[Anonymous No.15063740]

>>15063727
I guess you could do [eqn]\infty = \infty + 0 = \infty + \infty + (-\infty) = (\infty + \infty) + (-\infty) = \infty + (-\infty) = 0[/eqn] since associativity has to hold

[Anonymous No.15063743]

Can someone help me understand Steiner Systems, I know they can be represented by S(t,k,n), but I'm not sure what t,k, or n are.
When my professor told us to construct a Steiner Triple System of n = 3^k, he said we could simply say {u,v,w} is a line <-> u + v + w = 0. For a Steiner triple system of 2^k-1, he said it was u + v + w = 0 without a 0,0,0 point to make a Fano Plane. What's the logic behind this?

[Anonymous No.15063746]

>>15063732
Why not [math]\bigcup \mathcal{F} \neq \mathcal{F}[/math]?

[Anonymous No.15063749]

>>15063743
Steiner Triple Systems*

[Anonymous No.15063754]

>>15063746
yeah I typed one too many. I guess my condition holds for an ordered family of sets

[Anonymous No.15063841]

Anyone here know what they're doing with QP solvers?

A solver I'm using is demanding the quadratic term (S) be positive definite. I can't for the life of me figure out how to make it so.

My solution space looks something like this:
[w0, w1, w2,... |t0|, |t1|, |t2|...]
I'm driving the t's to be absolute values through some constraints.

My utility is: Max aw - wSw' - sum(abs(t))

Hopefully it's clear what I want, I just don't understand how to build a matrix that's positive definite such that [w, t] H [w, t]' = wSw' whilst also remaining positive definite + symmetric.

Any insight would be greatly appreciated.

[Anonymous No.15063878]

>>15063161
Impurities don't generally have to be isolated, you just test the product with the impurities.

[Anonymous No.15063939]

>>15045375
Notice that the voltage is AC, not DC. Also, that multimeter draws (ideally) zero current. The voltage of that fella's body may vary by +/-1.4V, but the actual charge is minimal. He couldn't supply any significant current at that voltage.

Where does the voltage come from? In short, mains power. All of the many power cables inside and outside your home are broadcasting at 60Hz (50Hz for the fella in the video as he's Australian). Your body is an antenna. He's got bare feet. When he steps to earth, he's grounded: 0V. When he steps up onto the wooden deck, he's no longer grounded and you can see the effect of the ubiquitous 50Hz.

Whether of not he stands barefooted in the dirt for 20 minutes each day makes no difference to his status as an antenna in this video.

[Anonymous No.15063957]

>>15063449
Sure thing.
https://archived.moe/sci/thread/14204690/#14246712
>>15063707
Extend every function in [math]Hom(X \setminus \{ x \}, Y)[/math] to [math]Hom(X, Y)[/math] by letting [math]f(x) = y[/math] and you get an explicit bijection.

[Anonymous No.15064173]

>>15063957
Thank you.

[Anonymous No.15064186]

Let [math]p,q[/math] be orthogonal projections in a complex Hilbert space [math]H[/math]. Assume [math]q-p[/math] is a positive operator, i.e. [math]\langle (q-p) \xi, \xi \rangle \ge 0[/math] [math]\forall \xi \in H[/math]. Apparently this forces [math]pH \subset qH[/math], but why?

[Anonymous No.15064220]

I have an n x n square matrix and I find that it has n different eigenvalues. Therefore I can conclude that this matrix is diagonalizable without any other calculations. Is this correct?

My reasoning is:
Since it has all different eigenvalues, its eigenvalues each have an algebraic multiplicity of 1
Therefore each eigenvalue has a geometric multiplicity (defined as the dimension of the kernel of the eigenspace generated by the eigenvectors associated to the eigenvalues) of 1, since 1≤geom multiplicity ≤alg multiplicity
therefore the sum of all geom. Multiplicities equals n, therefore the matrix is diagonalizable by a criteria for diagonalizable matrices.

Second question: does this make sense to someone that followed a different linear algebra course? I skimmed through a few English Lin alg books but most things were explained differently from my teacher and textbook, for example I couldn't find any mention of the Sylvester theorem while it was pretty important for my teacher, the spectral theorem was explained in a different way (even though it must mean the same thing)

[Anonymous No.15064290]

>>15064186
For an orthogonal projection [math]p[/math] and vector [math]u[/math], [math]0 \leq \langle pu, u\rangle \leq \| u \|^2[/math], with equality on the right if and only if [math]pu = u[/math].

For any [math]u[/math] such that [math]pu = u[/math], [math]\langle qu - pu, u \rangle = \langle qu, u \rangle - \|u\|^2 \geq 0[/math], and that can only be larger than or equal to zero if [math]qu = u[/math].
>>15064220
>Is this correct?
Yeah.
>therefore the sum of all geom. Multiplicities equals n, therefore the matrix is diagonalizable by a criteria for diagonalizable matrices.
Weird argument but I don't really remember goofy geometric multiplicity criteria.
>the spectral theorem was explained in a different way (even though it must mean the same thing)
There are fifty different spectral theorems and at least three for finite dimensional linear algebra (normal complex matrices, self-adjoint complex matrices, real symmetric matrices).

[Anonymous No.15064427]

Any good sources for understanding electric machines?

[Anonymous No.15064516]

>>15064290
Thank you!

[Aether king of sci No.15064519]

Is modern education only teaching us ad clicking?

[Anonymous No.15064523]

How do you keep your shit organized when writing a term paper/thesis?
Is it a good idea to have a txt with a brief summary of each paper I read and deem important for future reference? I only have very little experience with academic writing so far and most of it was a dreadful, soul crushing experience and I really don't want a repeat of it.
For one report where I only had to read 3 paper I printed them out and took notes on them, which helped a lot, but I don't think I can do that when I have to read a few dozens of them.

[Anonymous No.15064662]

If god is not real, why do the scientific names of both silver and gold begin with A? Checkmate atheists

[Anonymous No.15064738]

>>15064662

[Anonymous No.15064754]

What's the current consensus on altered metabolism from excessive dieting, leading to adaptive thermogenesis? I've struggled with weight gain if I eat anything above >1500 calories per day (I'm 6'0 160 lbs). My hands, feet, and basically anything except my core region of chest / stomach / groin area are constantly cold during autumn / winter. I'm not sedentary, as I run 3-4 times a week and walk to and from uni which takes roughly 60 minutes per day too.

I've tried just not giving a fuck, eating whenever I feel hungry, and that led me to gaining 45 lbs in 3 years. I've been on and off dieting for 12 years now, and getting really fed up with having to eat like a 5'0 100 lb chinese girl to not gain weight, because my hunger / appetite does not reflect my metabolism.

[Anonymous No.15064784]

>>15064754
How about you stop eating shitty foods?
What fraction of your intake consists of chewy, (dark) green foods? Spinach, apples, broccoli, &c.
If you eat normal food, not chips, pizza, and what else, and exercise as you say you do, you should not gain bad weight.
If you say you do despite eating well it is much more likely that you are lying than that you are some kind of genetic freak.

[Anonymous No.15064884]

>>15064754
I'm a similar build, and I run every day. During the hotter months, my appetite almost disappears. Like you, in wintertime, I become ravenous. I'm waking up in the middle of the night to eat. I don't use AC in the summer as I find the heat to be super comfy. This means the weight I do gain in wintertime is usually lost. Though I am careful each spring to ensure my weight is what I expect.

Consider using less AC in the summer months. Also, in wintertime, even if your home is kept reasonably warm, you can lose a lot of radiant body heat to an adjacent cold window.

I'd be interested in reading something on temperature vs appetite, too.

[Anonymous No.15065036]

Say that Y conditioned on X=x has a distribution G, with x as a parameter, furthermore lets say that X has a distribution H. How do you compute the characteristic function of Y in this case (without first determining Y distribution)?

[Anonymous No.15065114]

>>15064884
I live in northern Europe so AC is a foreign concept. My appetite remains constant regardless of temperature. Right now, although it's winter, my apartment is reasonably warm, and I'm wearing a t-shirt, a sweater + a padded jacket, but my hands are still icy cold, and my body gets cold too if I remain too stationary.

The only reason, thermodynamically, which could explain my reduced energy expenditure would be if my body altered the thermogenesis to save resources, only heating the important organs etc, and reducing the heat production in the periphery.

I tried going to my doctor with this, and he forwarded me to my hospitals' overweight division etc, but they rejected me because I wasn't overweight.

[Anonymous No.15065119]

how can i get work recognized as a amateur scientist with no affiliations?

[Anonymous No.15065152]

>>15064662
if god is not real then why is moral absolutism real?

[Anonymous No.15065365]

>>15065036
[eqn]\phi_Y(t) = \int_\mathbb{R} \left(\int_\mathbb{R} e^{it y} g_x(y) dy \right) h(x) dx

[/eqn]
Where [math]g_x[/math] is the density function of the distribution [math]G[/math] with the parameter [math]x[/math] and [math]h[/math] is the density function of the distribution [math]H[/math].

[Anonymous No.15065395]

is there a minimum incubation period or something between first exposure until gonorrhoea or chlamydia are first transmissible?

If I have unprotected sex with a girl on thursday night who exposes me to chlamydia and gonorrhoea , then I have a shower when I get back, a shower in the morning and then I have unprotected sex with another girl on friday evening and saturday morning , what are the chances I've given the second girl chlamydia or gonorrhoea considering that by monday morning my penis head is leaking smelly green/yellow discharge?

[Anonymous No.15065492]

sexhavers are fucking disgusting holy shit

[Anonymous No.15065704]

>>15065492
yeah it's pretty disgusting, and people who have stis are disgusting.
but then when it happens to you , you gotta role with the punches.

[Anonymous No.15065807]

What does the R to the upper left of the R mean. This is from set theory.

[Anonymous No.15065811]

>>15065152
The symbols mean the set of all functions from R to R

[Anonymous No.15065914]

For N a positive integer, suppose we have a random number generator (RNG) machine which produces a random positive integer between 1 and N (inclusive) each time we run it.

Let m_N denote the expected value, of the maximum length of an unbroken chain of increasing numbers, outputted from the RNG machine, if we run it exactly N times in a row. Obviously 1 ≤ m_N ≤N .

Should we expect that the limit of m_N exists as N goes to infinity? What about the limit of m_N / N ?

[Anonymous No.15065918]

>>15065152
If god is not real then why are there physical laws?

[Anonymous No.15065970]

>>15065914
m_N has to be at least sqrt(N) so it goes to infinity
my gut says it's exact value is also on the order sqrt(N) so m_N/N goes to 0
It wouldn't be difficult to compute the asymptotics m_N but I can't be assed

[Anonymous No.15065973]

>>15065914
what is even m_N's definition?
the maximum length is N, and it's expected value is therefore N.
Maybe it means m_N is the expected value of the length of unbroken chains?

[Your moms tapeworm No.15065976]

>>15065807
It stands for retard

[Anonymous No.15065985]

>>15064186
this means q is basically p but with some extra components left that contribute to making q-p positive.
So when you project using p, you keep less information than when you project using q.

[Anonymous No.15066000]

I'm not understanding the Axiom of Regularity. Say a set A = { {1}, {1,2}, {1,2,3} } exists. The axiom of regularity states that if x = {1}, x n A = 0 (empty set) but why wouldn't the intersection of x and A just be x?

[Anonymous No.15066021]

>>15065973
>Maybe it means m_N is the expected value of the length of unbroken chains?
Yes that's what I said.

[Anonymous No.15066022]

>>15066000
What would be in the intersection?

[Anonymous No.15066084]

>>15065395
With gonorrhea you'd be infectious right away - the Friday/Saturday girl has quite a high chance of contracting the disease if you weren't using condoms.
If this is based on a true story, let her know and advise her to get tested. It's common for gonorrhoea to be asymptomatic in women, but she'd still risk spreading it to anyone else she fucked.

[Anonymous No.15066159]

Does every finitely presented group act transitively by isometries on a compact riemannian manifold? I thought maybe you could do something with the presentation complex but I don't see how to make it work. Also since there's a universal finitely presented group, if it's possible at all it won't need manifolds of arbitrarily large dimension.

[Anonymous No.15066172]

Is "for almost all [math]x[/math]" used in math exclusively to indicate that a statement is true for all values of [math]x[/math] in a given set, except for a set of values that has measure zero, or can it also be used as an alternative to "for some [math]x[/math]"?

[Anonymous No.15066177]

>>15066172
google is your friend: https://en.wikipedia.org/wiki/Almost_all

tl:dr it's precise meaning depends on the content where it's used.

[Anonymous No.15066183]

I really need a good note taking app for an android tablet

[Anonymous No.15066191]

>>15066172
For all x in A
Means literally for every element in a given set, without exception
For all x in A such as φ(x) true
Means literally for every element in a given whose given property is correct.
For all x in A such as φ(x) is true, χ(x) is true
Is equivalent to
There is no element in A such as φ(x) is true, that verifies χ(x) is false.
The set of the elements that belong to A and have φ(x) true and χ(x) false is null. It can't even be a non-empty set of zero measure.
For some element in A such as φ(x) is true, χ(x) is true
Is equivalent to
For some elements in A such as χ(x) is true, φ(x) is true.

Note that universal existence does not work both ways, whereas conditional existence works both ways.

[Anonymous No.15066199]

>>15066191
>It can't even be a non-empty set of zero measure.
But can the expression "for _almost_ all x in A, such that φ(x) is true, χ(x) is true" be generally defined so that it refers to a non-empty set of zero measure? Is there such a measure?

[Anonymous No.15066514]

can anyone help me with this? it's due in 2 hours please help

translation:
"make an annotated parse tree for (5+4)/(6/2)"

[Anonymous No.15066520]

what should I put on my resume as my objective if I'm just applying for a chemistry TA position

[Anonymous No.15066522]

>>15066520
same thing you always put as your objective: long term career goals.

[Anonymous No.15066526]

>>15066159
Finitely presented groups are all countable, they can only possibly act transitively on zero-dimensional manifolds.

[Anonymous No.15066537]

>>15066514
help, for the love of god please help

[Anonymous No.15066543]

>>15066522
so you're saying I've been putting the wrong thing all this time!? maybe that's why I never got an internship

[Anonymous No.15066677]

I did some lab work today and i was breathing pretty dilute (but concentrated enough to smell them) fumes of nh3 and h2s. Now my head hurts and i feel really tired. Is this something i should worry about?

[Anonymous No.15066767]

Why does the system think links to articles are spam? We can't even post the DOI the system doesn't let it happen. Will this every be changed/fixed?

[Anonymous No.15066861]

>>15066526
Shit, I meant faithfully, not transitively, sorry

[Anonymous No.15066977]

>>15066861
Oh, right, I see.

The way [math]\mathbb{Z}[/math] acts freely on a compact manifold is already a mess, so I don't think there's a way to generalize that construction to all finitely presented groups, I don't think there's a way to produce some sort of quotient construction (build reps for the free groups and then quotient out the relations, fails because of the Z example and the compactness requirement) and I don't think you can embed it into [math]O(n)[/math] (because I don't think a single [math]O(n)[/math] has finite subgroups isomorphic to all symmetry groups to begin with).

I'd file it as "probably true but unprovable."

[Anonymous No.15067193]

Is 2 closer to infinite than 1

[Anonymous No.15067207]

Let [math]\mathbb{R}^{\mathbb{R}}[/math] be the vector space of all mappings from [math]\mathbb{R}[/math] to [math]\mathbb{R}[/math]. Let [math]V : \mathbb{R} \to \mathbb{R}[/math] be a fixed, continuous function. Decide if set [math] M := \{f \in \mathbb{R}^{\mathbb{R}}\ |\ f(x) = V(x)\ \text{for } x > 2\} [/math] is a vector subspace of [math]\mathbb{R}^{\mathbb{R}}[/math].

How's this meant? Can I choose whatever function [math]V[/math] I want? For example, could I define [math]V[/math] to be the constant zero polynomial? Or could [math]V[/math] be any continuous function?

[Anonymous No.15067209]

>>15067193
yes

[Anonymous No.15067211]

[Anonymous No.15067219]

>>15067211
The function is arbitrary but the answer depends on it's choice.
I would just elabrate that that is the situation and say what the answer would be depending on the unspecified properties of f (namely whether it is 0 for all x>2)

[Anonymous No.15067227]

>>15067219
Thank you, you already helped me. The rest I'll try to figure out myself. And one minor correction: I mistyped, it should've been "x > 0".

[Anonymous No.15067243]

Examples for real-valued functions that are differentiable but not continuously differentiable and that do not feature trigonometric functions in their terms?

[Anonymous No.15067282]

>>15065807
Could be a typo, what's the context of the question?

[Anonymous No.15067356]

>>15067243
[eqn] f(x) =
\begin{cases}
0 & x < 0 \\
x & 0 \leq x
\end{cases}
[/eqn]

[Anonymous No.15067428]

>>15067356
That's not differentiable at 0.
He wants a function whose derivative exists everywhere but isn't continuous, methinks.
But I dunno any examples that fit his criteria so who cares lmao.

[Anonymous No.15067431]

>>15067428
well if the derivative of the function isnt continuous at x, then its not differentiable at x either, right?

[Anonymous No.15067437]

>>15067431
Nope.
I understand why you'd think so, but a derivative can exist everywhere and fail to be continuous. Mean value still applies so all examples are very awkward but it's true.

Btw if you delete your posts I'm good with deleting mine.

[Anonymous No.15067448]

>>15067437
>all examples are very awkward
care to share with the class?
>Btw if you delete your posts I'm good with deleting mine.
oh thank christ, i wouldnt be able to sleep at night if historians of the future had evidence that the great satokofag made a mistake.

[Anonymous No.15067449]

>>15067448
>care to share with the class?
I can share my google results with the class, sure.
https://math.stackexchange.com/questions/292275/discontinuous-derivative
>oh thank christ, i wouldnt be able to sleep at night if historians of the future had evidence that the great satokofag made a mistake.
Eh, do what thou wilt.

[Anonymous No.15068210]

>>15067565