/sqt/ /qtddtot/- stupid questions thread

[Anonymous No.10263327]

Any and all questions can and should be reposted on >>>/wsr/
Advice should go on >>>/adv/, but you can obviously request it here. Advice about the engineer life can also go on >>>/sci/eng/ , and advice about learning mathematics and solving problems on >>>/sci/mg
Questions about technology go on >>>/g/sqt . Questions about computer science can and should be reposted there.
Questions like "my fridge isn't working how do I scientifically fix it" go on >>>/diy/sqt , not here.
Questions about engineering can be reposted on >>>/sci/eng
Good questions about maths can be reposted on >>>/sci/mg Please keep your undergrad homework here.
If >>>/sci/pg/ is up, good physics questions can also go there. Similarly, please remember that thread exists for fun.
Questions like "how do we fix /sci/" and "why did hotpockets delete my thread" go on the IRC or >>>/qa/
The wiki in the sticky is a marvelous resource for recs, and >>>/sci/big is often a font of charts. Books can usually be downloaded on libgen.io , and if they can't, >>>/wsr/ is fantastic at tracking them down.

Please write your questions clearly, and make sure any image is flipped correctly. Thanks are always appreciated, and are appreciated more with cute images.

[Anonymous No.10264721]

Regarding precision measuring instruments (such as calipers, micrometers, scales, etc.), how far does the calibration chain go?

Many companies use calibrated measuring instruments to get the job done, and every year (or other arbitrary timeline) they send them off to get calibrated so that they stay accurate.

How do the calibrators know that their equipment is accurate? Who calibrates the calibrators?

[Anonymous No.10264726]

How do I become less autistic and make connections while studying? I'm already getting good grades but I'm worried that I'm missing the social skills.

[Anonymous No.10264946]

>>10263327
how do people write math symbols in 4chan threads on /sci/

[Anonymous No.10264988]

>>10264726
Start small. No matter how autistic you are, someone will always be more autistic than you.

If studying local, make friends with the engineering & compsci students. If studying abroad, go to Germany, Japan, or Singapore.

[Anonymous No.10265035]

>>10264721
>How do the calibrators know that their equipment is accurate? Who calibrates the calibrators?

They use (potentially very expensive) standards, which are again manufactured by someone else. At the end of the chain is usually a national standards institude (e.g. NIST, NPL) who spend their entire budget doing maintaining high-quality standards.

[Anonymous No.10265046]

>>10265035
Call me a retard if you have to, but how does the end of the chain know that they're accurate?

[Anonymous No.10265064]

help im retarded

I dual majored in Biochemistry and Molecular Biology (that was one thing) and Biology. How do i put that on a resume without sounding retarded.

[Anonymous No.10265095]

>>10265064
two separate lines to make it bigger

[Anonymous No.10265299]

I need to find the unit for U

in
Q=U*A*ΔT*t

Where Q=Watt
U = λ/m1
A= m^2
ΔT = kelvin
t= seconds

I forgot how to rewrite a formula to find a specific unit.
Anyone who can help me out?

[Anonymous No.10265361]

>>10264726
Feynman's method is probably what you're looking for. If you're getting good grades, there probably is someone in your class who wouldn't mind studying with you.
>>10264946
Picture in the OP.
>>10265299
U=Q/(A* T*t)
U=watts/(m^2 kelvin seconds)

[Anonymous No.10265379]

>>10265046
> but how does the end of the chain know that they're accurate?
Historically, the end of the chain was a physical prototype held in a vault at the BIPM headquarters near Paris (for the kilogram, this is still the case until May 2019). The prototypes are correct by definition: a metre IS (or was) the length of the metre prototype.

More recently, the definitions have been based upon physical quantities, so anyone capable of constructing the relevant apparatus has a reference that's as good as any other. The last hold-out was the kilogram, but from 20 May 2019 it's derived from the existing definitions of the metre and second and the Planck constant.

[Anonymous No.10265493]

>>10265361
>U=watts/(m^2 kelvin seconds)
its without seconds.

[Anonymous No.10265495]

Can anyone help me understand this. Its seems like the differential operators should only act on the e^(iwt) within the fourier transforms to produce the -w^2 factors but I can't figure out how.

[Anonymous No.10265507]

>>10265495
Forgot picture.

[Anonymous No.10265543]

>>10265507
I don't think it's the curl operators that give you that anon. The w^2 come from the time derivatives on the right.

[Anonymous No.10265550]

>>10265543
Yeah I should have said that. If I fourier transform the LHS then the right hand side has to have the same done to it. So for any one of the terms there will be a electric field or polarisation acted on by the time operators, then that will be fourier transformed. So the time derivatives shouldn't be able to act on the exponential factor of the fourier transform.

[Anonymous No.10265563]

>>10264946
[Catalog] >> /sci/guide
>> https://sites.google.com/site/scienceandmathguide/
>> /sci/ LaTeX Tutorial
(or read image in >>10263327)

for testing, try your code at
https://latex.codecogs.com/eqneditor/editor.php
http://www.sciweavers.org/free-online-latex-equation-editor

right-click on pretty formulas
to see the code that produced it

protip: put a space before each backslash

[Anonymous No.10265584]

>>10265550
I guess thats a more rigorous way to do it than mine but you get the same result, the transform of an nth derivative gives you an extra w^n.

https://en.m.wikipedia.org/wiki/Fourier_transform#Functional_relationships

[Anonymous No.10265628]

>>10265584
Ah thanks, didn't think to search fourier transform of a derivative.

[Anonymous No.10265701]

How do i rewrite :

Ua * ΔTa = U * ΔT

to

ΔTa/ΔT = U/Ua

[Anonymous No.10265709]

>>10265701
We divide both sides by [math]\Delta T[/math], and get [math]\frac{Ua \Delta Ta}{\Delta T}=\frac{U \Delta T}{\Delta T}[/math]. We cancel out both [math]\Delta T[/math] on the right to obtain [math]\frac{Ua \Delta Ta}{\Delta T}=U[/math].
Dividing both sides by [math]Ua[/math] we get [math]\frac{Ua \Delta Ta}{\Delta T Ua}=\frac{U}{Ua}[/math]. Then we cancel out both Ua on the left to obtain the desired expression.
Dividing both sides by [math]Ua[/math] we get [math]\frac{Ua \delta Ta}{\delta T Ua}=\frac{U}{Ua}[/math]. Then we cancel out both Ua on the left to obtain the desired expression.

[Anonymous No.10265712]

Does the pineal gland truly produce DMT when dying or while sleeping?

[Anonymous No.10265715]

>>10265709
Thanks a lot man

[Anonymous No.10265717]

>>10265712
https://www.ncbi.nlm.nih.gov/pubmed/29095071

[Anonymous No.10266011]

Is the following partial differential equation elliptic, parabolic or hyperbolic, or none of these types?

[math] \nabla \cdot (f \nabla u) = 0 [/math] in [math]\Omega \subset \mathbb{R}^3 [/math],
where [math]f:\mathbb{R}^3 \rightarrow \mathbb{R}$[/math] is known but not constant, and [math]u:\mathbb{R}^3 \rightarrow \mathbb{R}$[/math] is the unknown function. Also [math]f>0[/math].

[Anonymous No.10266023]

>>10265064
>biochemistry and molecular biology and biology
There's so much overlap it should have just been called biochemistry.

[Anonymous No.10266053]

>>10266023
We need to separate the people who actually know things about chemistry and apply them to biology from the people who just study fish olfactory receptors, bird calls, and drosophila intestines

[Anonymous No.10266175]

what's are some recommended textbooks used in genchem lab classes that is theory and explanation oriented? similar to pic, williamson's organic experiments, its contents are centered around the theory behind the procedures of each experiments, and not just following the procedures of the experiments.

[Anonymous No.10266199]

>>10266053
but we need people who truly understand a complex organism to evaluate biochemical findings

[Anonymous No.10266266]

Given subspaces of [math]\mathbb{R}^{3}[/math], [math]U_{1} = \{ (x,y,0)\in\mathbb{R}^{3} : x,y\in\mathbb{R}\}[/math] and [math]U_{2} = \{ (0,w,z)\in\mathbb{R}^{3} : w,z\in\mathbb{R}\}[/math]. I know that [math]\mathbb{R}^{3} = U_{1}+U_{2}[/math] but I'm trying to show why [math]\mathbb{R}^{3}\neq U_{1}\bigoplus U_{2}[/math]. Could I just observe that the union of standard basis of [math]U_{1}[/math] and [math]U_{2}[/math] doesn't allow all vectors in [math]\mathbb{R}^{3}[/math] to be written as a linear combination? Or is there a more 'direct' (get it?) way to do it (i.e. finding a counter-example, etc).

[Anonymous No.10266280]

Just got through a beginner's course in LaTeX and Christ is it an amazing application. Why isn't it used more compared to WYSIWYG apps?

[Anonymous No.10266294]

>>10266266
The direct product has a basis with four elements.
That is all.

[Anonymous No.10266295]

>>10266266
nevermind, [math](1,2,3) = (1,2,0)+(0,0,3) = (1,0,0)+(0,2,3)[/math] works.

[Anonymous No.10266296]

>>10266294
brainlet here, how do you show that?

[Anonymous No.10266299]

>>10266296
U_1 and U_2 have two element basis.

[Anonymous No.10266303]

>>10266296
direct product means intersection is trivial, i.e. it has dimension zero. but dimV+W = dimV + dimW - dimV∩B. so it's not possible.

[Anonymous No.10266306]

>>10266299
{(1,0,0),(0,1,0)} and {(0,1,0,),(0,0,1)} right?

[Anonymous No.10266312]

>>10266306
Yah.

[Anonymous No.10266325]

>>10266303
why is dimV∩W =0 in my example?

[Anonymous No.10266333]

>>10266325
It isn't, anon goofed his notation.
Essentially, the direct sum and the normal sum of subspaces are equal only when the intersection is 0.
That does also work for the proof tho.

[Anonymous No.10266334]

>>10266325
it's not, that's the fucking point

[Anonymous No.10266483]

What is that sketchy site that bypasses journal paywalls?

>>10266280
Windows and other proprietary software are demonstrations of plato's allegory of the cave

[Anonymous No.10266500]

Given an explicit basis B for vector space R^n, I know how to find its dual basis - the gist of the matter is to write B's vectors as the columns of a matrix, find its inverse, and then the rows of the inverse are the linear functionals that make up the dual basis B*.

However, what if for example we have a vector space V = span{[1,2,0] , [3 3 4]}, where the basis B for the space is simply the two given vectors that span V? How can I find **B's** dual basis? There is no inverse for the 3x2 matrix defined by those vectors as the matrix is not square.

Many thanks in advance.

[Anonymous No.10266508]

>>10266500
OP here, just wanted to add that a thought that came to my mind is to try and complete B into a basis for R^3, then find ITS dual basis (by computing an inverse matrix), but discard the 3rd functional given from this method. However I'm not sure if my reasoning is sound and if so how to formally prove it.

[Anonymous No.10266551]

>>10266483
Thanks for the response!
Unpaywall? They say they provide it for about 53% of all on the internet (23.7 million, which is still plenty). You can go through the site or use the Chrome or Firefox extension.

[Anonymous No.10266591]

>>10266483
>What is that sketchy site that bypasses journal paywalls?
scihub?

[Anonymous No.10266594]

>>10266500
there's an addition to that algorithm for non square matrices in which you pretty much add identity columns in some places to make it work

[Anonymous No.10266595]

>>10266591
Yes! Thanks!

[Anonymous No.10266620]

>>10266500
>pips sip
You could find a set vector that completes the span to the whole R^n and do the usual, then remove the duals of the new ones.
Then again, I've forgotten that shit.

[Anonymous No.10266651]

>>10266508
>complete B into a basis for R^3, then find ITS dual basis (by computing an inverse matrix), but discard the 3rd functional given from this method
yes, you can do this. you complete (u,v) to a basis (u,v,w) of R^3 and find the ususal dual basis, say (f,g,h). now h kills u and v, hence your subspace. and we can throw it away. f and g are defined on all R^3 and they depend on the choice of the third basis vector w. however their restriction to span(u,v) does not and is exactly the dual basis for (u,v) IN THE subspace span(u,v). please note that by definition the desired dual basis cannot be defined on whole R^3 but only on the subspace. it doesn't make sense otherwise.

[Anonymous No.10266699]

>>10266651
Gotcha. Thanks a lot to all who replied. I'll dig deeper into the subject

[Anonymous No.10267256]

>>10266266
Two subspaces form a direct sum if and only if their intersection is [math]\{0\}[/math]. You have two planes in [math]R^3[/math] going through the origin. The planes are defined by a basis of two elements, so joining the two bases define a spanning set of [math]\mathbb R^3[/math] with 4 elements. But any basis of [math]\mathbb R^3[/math] has exactly 3 elements. Hence, there must be a linearly dependent element. Equivalently, they don't intersect as [math]\{0\}[/math]. Geometrically, this is because two planes through the origin can either intersect in a line, or be the same plane.

[Anonymous No.10267391]

>>10266011
When you have non-constant coefficients you have to look at the Hessian of [math]f[/math] near each point. It can become elliptic/parabolic/hyperbolic at different points in [math]\Omega[/math].

[Anonymous No.10267710]

The vertices of a triangle are P(- 3, 1, 2), Q( 1, - 3, -1) and R(3, -1, -1)
a) Verify that triangle PQR is a right-angled triangle.
b) A median of a triangle is a line that joins a vertex to the midpoint of the opposite
side. Find the vector that represents the median from P to the side QR.
c) Determine the perimeter of this triangle PQR
d) What are the coordinates of S(x,y,z), such that PQRS is a rectangle?

Can someone help me with b and d. I calculated the midpoint to 2,-2,-1 but I don't know how to find the vector p to m. I subtracted them but I don't think that's right. I get the idea of a postion vector but I can't visualize this at all. Wouldn't d just be twice the value of whatever p to m is. Thank

[Anonymous No.10267728]

[math] \int_{a}^{b} [/math]

[Anonymous No.10267730]

>>10267728

yay I did it :D

[Anonymous No.10268054]

>>10267710
> I calculated the midpoint to 2,-2,-1 but I don't know how to find the vector p to m. I subtracted them but I don't think that's right.
It's just m-p = 5,-3,-3

> Wouldn't d just be twice the value of whatever p to m is.
S = Q+(P-Q)+(R-Q) = P+R-Q =

In the general case, PQRS would be a parallelogram (Q-P=R-S, R-Q=S-P), but as PQR is a right angle it's a rectangle. You can confirm this by applying Pythagoras at all 4 corners: PQR, QRS, RSP, SPQ.

[Anonymous No.10268056]

I am preparing for an upcoming exam.
Electrochemistry, redox reactions and gases are my last subjects to check up on.
I have a problem with incomplete redox reactions.
Basically I need to think of the possible product before I can even begin to balance the reaction and start to answer the question.
What should I look up on if I want to know how to determine the correct products of a reaction?

[Anonymous No.10268057]

>>10267728
>>10267730
based

[Anonymous No.10268156]

So I'm currently learning Algerbra onwards for university and I'm completely stumped when I get questions like this. What am I doing wrong? Why isn't "100+20*5*1/4" correct? I don't understand and need help understanding why I'm wrong so I can improve.

[Anonymous No.10268158]

Is partial integration a commutative operation?

[Anonymous No.10268162]

>>10268156
>Why isn't "100+20*5*1/4" correct?
Read up on what 5 1/4 means, it's NOT 5 * 1/4, but 5 + 1/4.

[Anonymous No.10268169]

>>10268162
Sorry to be a bother, but I still don't understand. Where can I read up on what 5 1/4 means? Pic related, what I got when I used that formula.

[Anonymous No.10268172]

>>10268158
What exactly is that supposed to mean?

[Anonymous No.10268177]

>>10268162
>>10268169
Okay, NOW I got it. I'm sorry that it's a stupid question. I grew up hating math and have to teach myself this stuff as an adult to get into the fields I want.

[Anonymous No.10268182]

>>10268172
For example 2 I can't tell if my integrations are off because I tried integrating wrt x, then y and my solution was different.

[Anonymous No.10268184]

>>10268182
>For example 2
?
>I can't tell if my integrations are off because I tried integrating wrt x, then y and my solution was different.
You have to change the domains of integration, then you can also change the variables of integration, that is Fubini's theorem.

[Anonymous No.10268185]

>>10268182
>>10268172
Forgot the pic

[Anonymous No.10268193]

>>10268185
Well, it shouldn't really make a difference.

The solution for u_xyy is also a solution for u_yxy, as partial derivatives are interchangeable and a rough calculation in my head tells me that the result is the same for each order of differentiation.

What do you get for other orders of integration and what does this have to do with partial derivatives?

[Anonymous No.10268210]

>>10268193
I actually got a correct answer when changing the order I integrated in. I don't know why I didn't think of just differentiating WRT x once and y twice to just check if I was making a mistake. Thanks bud.

[Anonymous No.10268231]

Solve equation:

>x1=2, x2 =4, x3=6; n=3

So this is quite elementary......
Elaborate how to place x- 1 and such in their specific part in this equation? Hopefully someone gets what I mean.

[Anonymous No.10268235]

>>10268231
Do you see the large Sigma? Do you know what it means?

[Anonymous No.10268472]

are there any (legal) research chemicals or drugs that will make me cum instantly? it takes me too long to masturbate, i just want to be able to cum as quickly as possible so i can get on with my day. serious answers only.

[Anonymous No.10268482]

>>10268472
No, there aren't.

[Anonymous No.10268650]

>>10267728
you can preview your latex by click on the TEX button of your quick reply box

[Anonymous No.10268659]

>>10268158
It's the same thing as when does [math]\frac{\partial f(x,y)}{\partial x\partial y}\stackrel{?}=\frac{\partial f(x,y)}{\partial y\partial x}[/math]. And the answer is when the integrand (or the derivand) is nice enough, usually meaning continuous almost everywhere (or twice continuously differentiable). If you integrate and get a function that is not twice continuously differentiable, then chances are that partial integration will not be commutative.

[Anonymous No.10268772]

I've found out some weird things about particular discipline I'm into. But I'm still in the phase of confirmation bias. I want to believe. How do I perform the final step to accept the truth

[Anonymous No.10269194]

can ice cut?

[Anonymous No.10269199]

>>10269194
no, but a tin can

[Anonymous No.10269279]

>>10268659
It's not the same thing, https://en.wikipedia.org/wiki/Fubini's_theorem One basically applies always, and the other needs C^2 smoothness.

[Anonymous No.10269292]

>>10269279
Yeah, I meant like conceptually it's the same idea but backwards, but since integration "smooths" stuff you only need continuous almost everywhere (or even less with Lebesgue integral)

[Anonymous No.10269330]

I saw a video about animal extinction years back.
I think it was on nature or science.
Upon checking all their videos I did not find it.
Anyone remembers a video about a paper like this:
>investigated animal extinction as a result of global trade
>espacially coffee and its different trade routes.

thanks

[Anonymous No.10269370]

>>10265064
Biochemistry & Molecular Biology(,) and Biology

[Anonymous No.10269471]

>>10268472
Heroine makes it easy.

[Anonymous No.10269478]

Why i cant sleep if i listen to my favorite songs before going to bed? Even when i'm very sleepy

[Anonymous No.10269589]

>>10269478
Because it produces dopamine and if you fell asleep it wouldn't produce dopamine.

[Anonymous No.10269647]

>>10269589
Also sex produces dopamine but people (especially males) say they can fall asleep better after it

[Anonymous No.10269652]

>>10269647
They use the refractory period to do that.

[Anonymous No.10269712]

>>10265064
Did a similar thing I usually put

Majors:
Mathematics & Physics
Computer Science

[Anonymous No.10269795]

>>10269712
>mathematics and physics is a major now
The university was a mistake.

[Anonymous No.10269800]

>>10269795

well its essentially the math major + physics major, we have a 3 tier system so it's a "specialist major", compared to a regular "major"

[Anonymous No.10269810]

>>10269800
>the formatting suddenly changed in between posts
Always get the impression someone else is responding just for jokes.
What are the other tiers?

[Anonymous No.10269823]

>>10269810
Specialist which is ~12/20 credits
Major which is ~10/20 credits
Minor which is like ~4 credits

To graduate you either need a specialist, 2 Majors or a Major and 2 Minors

[El Arcón No.10270545]

How about that time circuit?

[El Arcón No.10270551]

>>10270545

[El Arcón No.10270555]

>>10270545
>>10270551

[El Arcón No.10270557]

>>10270555

[El Arcón No.10270559]

>>10270545
>>10270551
>>10270555
Time arrow spinors

[Anonymous No.10270601]

>>10270557
What went wrong in this proof?

[Anonymous No.10270611]

>>10270601
every single line is bullshit

[Anonymous No.10270612]

>>10263327
best telescope for 100 dolla?

[Anonymous No.10270621]

>>10270611
I know this proof was removed for that reason, but why is it bullshit to consider some complex number which takes that form? I mean, I don't know what the hell "infinity hat" is but if that makes sense then it makes sense to plug it into the Euler product. it wouldn't prove the hypothesis but it doesn't appear to be complete bullshit, but maybe it's saying something completely nonsensical.

[Anonymous No.10270746]

Should a biology student study chemistry or physics?

[Anonymous No.10270793]

>>10270621
> I don't know what the hell "infinity hat"
Nobody does, not even the author of this "proof".

>if that makes sense
It doesn't.

[Anonymous No.10270820]

>>10270746
physics, chem is the middle path but will not lead you to great power or understanding, only steady income and banal 6-8/10 gf's with nice tits and low bf%

more importantly chemistry is for people too dumb for physics and not creative enough for the brainchad fields in bio (mol bio, genetics, biophysics)

[Anonymous No.10270843]

>>10270820
I want to study physics but I'm getting shoehorned into chem for marine shit, oh well

[Anonymous No.10271029]

I’m having an issue finding an old math problem. It is either a diophantine or modular arithmetic problem, and I think Euler (or some other famous mathematician) presented it to another famous mathematician. A few decades ago, the problem was found, and given as a challenge to a bunch of Olympiad participants, and none of them solved it in time. One of the people involved spent months writing a paper solving a more general version of the problem (and succeeded). What is this math problem? I now I read a book about this piece of history, but now I can’t find it.

[Anonymous No.10271067]

Something I've never understood about ODEs.

Suppose you have y' = x/y

I'm aware this easily solved via separation, but why isn't it acceptable to just integrate wrt y to solve this?

[Anonymous No.10271113]

>>10271067
The reason separation of variables works at all takes a lot of explanation, and extra nuance, so don’t expect to be able to use similar tricks at all. To answer your question, it’s because you are trying to define y in terms of x. If you immediately try to integrate this, you get y = integral y/x dx + C, which you don’t know how to solve, because you don’t know what y is in terms of x.

[Anonymous No.10271127]

>>10271067
Separation of variables has some nuances, and a lot of extra math behind it, so don’t base your understanding of differential equations off of separation of variables. To answer your question, because integrating with respect to y doesn’t solve the problem. If you integrate the right hand side wrt y, then you don’t know the solution, because you don’t know what x is in terms of y, and the left hand side is integral dy/dx dy, which doesn’t simplify to anything.

[Anonymous No.10271365]

I am self-taught, can anybody explain me, step by step, how to read/interpret the 'switching states table' of this circuit? thx

[Anonymous No.10271619]

for the same reason that it's "irrational" to play the lottery, could you say that in many cases it's not worth it to buy (non-mandatory) insurance? because with insurance you may be paying for other people's risky behavior, for insurance fraud payouts, as well as the insurance company's expenses and profit. and often there are other ways to control the amount of risk you take besides buying an insurance.

[Anonymous No.10271675]

>>10271619
Yes. Economically insurance isn't worth it, the average person will loose more then he gets out of it (at least with commercial insurances).

People buy insurances to minimize the risk of something horrible happening to them which on average is an irrational fear for the price they are paying, pretty much the opposite is true for lotteries, people bet on a slight increase for their material wellbeing.

Essentially the difference is that people who are pessimistic insure themselves and optimists play lottery. Personally I would call the pessimists a lot more rational.

[Anonymous No.10271682]

>>10271619
Paying insurance only makes sense when you're planning on cheating the insurance company.
Or when you're a pussy.

[El Arcón No.10271685]

>>10270601
Nothing went wrong with the proof. The problem with the human culture. Corollary from here:
Real Numbers in the Neighborhood of Infinity
http://www.vixra.org/abs/1811.0222

[Anonymous No.10271747]

>>10271619
both lead to less money and hence decreased quality of life. While winning the lottery could give you all you hope for and more (not really), insurance acts as a safety net for your life. True, insurance companies work so that they have a net positive, but for every 1000 "suckers" who pay all their life and their house never burns down, there's 1 who does and thanks to insurance, doesn't go completely bankrupt. And surely 1/1000 chance is higher than the 1/1000000 chance of winning the lottery.

[El Arcón No.10271776]

[El Arcón No.10271782]

>>10271776

[El Arcón No.10271788]

>>10271776
>>10271782

[Anonymous No.10271805]

Can someone make the notion of dependency set clear to me?

[Anonymous No.10271828]

>>10270746
If you have no specific aims, you should actually choose math. Few Bio courses give you robust exposure to higher mathematics in normal course, and those skills are only going to get more valuable to your primary field in the future.

Unless you absolutely know you need specialist knowledge from either chemistry or physics ahead of time, go with math.

[Anonymous No.10272523]

Can I ever hope to understand inter-universal Teichmüller theory with an IQ of ~110?
Which field of math would I need to specialize in, to have the best chances?

[Anonymous No.10272544]

>>10272523
Mochizuki's IQ is probably lower than Scholze's.
The requirement for understanding IUT is currently unknown to man. Probably profound wisdom, knowledge of self, faith in our Lord Jesus Christ and a genuine comprehension of Euler's great equality flat=justice.

[Anonymous No.10272558]

Is it normal that a lot of times after i masturbate and go to the toilet to clean up/pee while sitting down, I get the urge to poo a bit?

It also happens when I get very blueballed with a girl (like a lot of penetration but i dont end up coming). Like 15-20 mins after, I get this intense pain that is not unlike constipation, and I often also get the need to poo (it doesn't completely solve the blueball problem).

I know there's some anus-cock connection that the gays exploit, but is this related or what?

[Anonymous No.10272566]

>>10272523
at least an advanced-undergraduate knowledge of the theory of heights, which is hilariously Scholze's nemesis

[Anonymous No.10272627]

Could you give me a quick run down around the psychology and all of the needed requirements?

[Anonymous No.10272983]

let [math] \ f:[a,b) \rightarrow \mathbb{R} [/math] be differentiable twice.
prove that if [math] \ f''(x) > 0 [/math]
then [math]\ g:(a,b) \rightarrow \mathbb{R}
[/math] defined [math]\ g(x)=\frac{f(x) - f(a)}{x-a}[/math] is strictly rising.

I've managed to solve this but I did it in a pretty brainlet-ish time consuming way. Can someone point me to an easy solution for this?

[Anonymous No.10273052]

What's the statystical probability of this occurring?
>>>/v/445624459

[Anonymous No.10273085]

May 21st 2012

[Anonymous No.10273381]

So usually the curving of spacetime by matter is depicted on a 2d plane. In this 3d representation I think I can better understand spacetime as an universal "aether" ( that term seems like it makes more sense than "fabric") that just exists to the ends of the universe. On to my question: does this mean that when its said gravity is caused by the bending of spacetime that gravity is the result of the recoiling/tension of spacetime trying to straighten itself back out?

[Anonymous No.10273394]

There are many things. There is this set one may call "everything". Everythings seems a like bigger word than eternity or infinity.
Where to start?

[Anonymous No.10273531]

On fossil fuels: if we created a massive shit pit to be filled and buried by the next 500 or so years, how long would one expect it to take for the material to break down into some kind of usable biomass or fuel? Could pressure and time eventually turn our once shit pit into a future tar pit?

[Anonymous No.10273714]

>>10272523
>In September 2018, Mochizuki wrote a 41-page summary of his view of the discussions and his conclusions about which aspects of his theory he considers misunderstood.[13] In particular he names:
>"re-initialization" of (mathematical) objects, making their previous "history" inaccessible;
>"labels" for different "versions" of objects;
>the emphasis on the types ("species") of objects.
???

[Anonymous No.10273766]

x1 ∙ mA = x2 ∙ mB
x1 ∙ 2mB = x2 ∙ mB
x1 ∙ 2 = x2


Can i really just remove mb out of this equation?

[Anonymous No.10273771]

>>10273766
If it is non zero I think so.

[Anonymous No.10273802]

Can someone explain to me how you do this?
rewriting the first formula to get the second one.

[Anonymous No.10273861]

What would happen if a star went supernova within 10 ly of earth?

[Anonymous No.10273862]

>>10273802
Do you know about multiplication and division?

[Anonymous No.10273864]

I throw a coin in the air 5 times. It lands on heads every single time.
I throw it once more, is the probability that it lands on heads another time 50%, or 1.5%?
If it's the lowest chance, well of course it makes sense since there should be a low probability of an event happening several times in a row.
If it's 50%, then it also makes sense since the coin itself doesn't change in any way, thus it should stay at 50%, if you were not told of any of the previous outcomes, you should still think it's 50%.
Which one is it?

[Anonymous No.10273891]

>>10273864
50%
See gambler's fallacy.

[Anonymous No.10273903]

>>10273864
https://www.youtube.com/watch?v=tP-Ipsat90c

[Anonymous No.10273910]

>>10264721
To simplify this, as I've questioned this myself in the past...

Imagine a lab that spends millions or billions to be able to be able to measure things with the highest accuracy and precision known to man. This becomes the gold standard.

These labs are good at creating standards and measuring things but theyre not particularly fast at doing so as the methods are painstainkingly tedious and slow. Another company says "I can create a process that is faster then those labs, but is maybe less precise but fairly accurate". This gets repeated a few times and you end up with companies who can calibrate things to various precisions taking different amounts of time with different costs.

[Anonymous No.10273915]

>>10265046
They don't necessarily know they are accurate. Part of measurement analysis is realizing that accuracy comes down to multiple independent processes (which may or may not be similar) agreeing with eachother. This is why no single lab could exist and call itself accurate, it needs to be confirmed with other labs (the more the better). If you have 100 labs agreeing on the mass of an electron down to 5 decimal places let's say, you really start to have great confidence in that measurement.

[Anonymous No.10273921]

>>10273864
the scientific observation points to 100% chance of landing on heads.

Now you can have a confidence interval around 100%, but if I pointed a gun at your head and made you call heads or tails you wouls call heads.

[Anonymous No.10273948]

>>10263327
>10268231
what are the modes of black holes? intuitive explaination, please.

[Anonymous No.10273958]

>>10273864
If the coin is assumed to be fair, then it's 0.5. If you consider the possibility that the coin might have a bias, you can't know the probability without some information as to the probability of the coin having a given bias. The lower the probability of the coin having a bias, the more likely it is that the 5 successive heads is just chance (it's expected to occur 1/32 for a fair coin) and the closer the probability will be to 0.5. If a biased coin is more likely, then the probability will be higher (assuming that the probability of bias is symmetrical, the fact that you got 5 heads makes a coin biased towards heads more likely than a coin biased towards tails).

[Anonymous No.10274028]

hey, ideas for how to improve short term memory? i think im getting worse over time these days to remember simple shit like what was said in a conversation or what someone was wearing

i'm thinking either im slowly becoming more retarded than i already am, or i just don't pay attention (which is probably just as likely)

any ideas how to work on improving attention or memory?

[Anonymous No.10274104]

>>10269199
thanks for the giggle <3

[Anonymous No.10274114]

>>10274028
Good sleep and paying attention.

[Anonymous No.10274123]

>>10264721
they just need to be one or two power of tens more precise than the measuring instruments they're calibrating. use a chunk of metal that has been verified to be a certain length/weight and is unlikely to degrade or use lasers and whatnot

[Anonymous No.10274145]

>>10273862
can you just explain the steps

[Anonymous No.10274148]

>>10270612

grandmas binoculars and toilet paper rolls

[Anonymous No.10274175]

>>10263327
If I wanted to test the effectiveness of a medication based on the average lifespan of test subjects (whether or not that's really a good way to do it), should I used a two sided interval or a one sided interval? Now I figure it would be the latter for obvious reasons but I could be wrong.

[Anonymous No.10274195]

>>10274028
What >>10274114 said and maybe try adding some lions mane to your diet. (Mushroom)

[Anonymous No.10274327]

I need help on a major life decision. I know this is advice and it technically it should go in \adv\ but \sci\ is the target audience I am looking for.

I started out as a bio major as pre-med. It was going well until I found out that I have to report all classes taken even outside of a 4 year institution. When I was in 10th grade my parents signed me up for Calc 1 and Chem 1 over the summer at CC. I fucked around and got an F in calc and C+ in chem but I did alot better in these classes in uni but I still have to report them which would kill my science gpa.

I have been having second thoughts about med school even before I found this information out and seeing that its almost not possible I would like to make a shift. I took an intro CS class just to see how it is and enjoyed it alot.

So my main question after all this backstory is that is there any value in someone with a BS in CS and Bio? We do have a biotech degree program but the classes I would have to take in the bio tech degree are similar to CS and I would just be a few classes off from an actual CS degree.

Also if it helps any way I live in New Jersey and my university is Rutgers....i have heard that new jersey has a nice biotech field.
Thanks for listening.

[Anonymous No.10274363]

opps i meant to make a thread

[Anonymous No.10274375]

How long should it take me to learn ODE, PDE's and vector calculus to a sufficient degree that I would be capable of understanding Maxwell's equations? I have elementary knowledge of differential and integral calculus. By elementary knowledge I mean all the rote memorized techniques for differentiation and integration as well as for testing the convergence or divergence of series and determining power, taylor and mclaurin series.

[Anonymous No.10274397]

Any good "crash course" in elementary group theory and ring theory? I'd to review algebra for an exam but there's no notes and textbooks are a bit too long for my timeframe

[El Arcón No.10274410]

[El Arcón No.10274420]

[El Arcón No.10274426]

[Anonymous No.10274430]

>>10274375
>understand
If you mean literally look at them and understand the notation, 5 mins.
https://en.wikipedia.org/wiki/Partial_derivative
https://en.wikipedia.org/wiki/Gradient
https://en.wikipedia.org/wiki/Curl_(mathematics)
If you mean "be capable of solving them and understand the derivation", a week should work.

[El Arcón No.10274436]

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[El Arcón No.10274439]

[El Arcón No.10274458]

[Anonymous No.10274459]

>>10274397
another university's course notes. Like literally any. Just google abstract algebra course *your favorite uni*, and compare what you need to know with what's there

[El Arcón No.10274460]

[El Arcón No.10274472]

[El Arcón No.10274476]

[Anonymous No.10274554]

>>10273381
Not even wrong

[Anonymous No.10274570]

>>10274410
>>10274420
>>10274426
>>10274436
>>10274438
>>10274439
>>10274458
>>10274460
>>10274472
>>10274476
Why did you dump that in the questions thread?

[El Arcón No.10274604]

Things that are correct form a subset of things that are not even wrong.

>>10274570

[Anonymous No.10274605]

>>10268056
The properties of the reactants. There is nothing specific for this to learn, it's very general. It goes from easier stuff like knowing that halogens will usually end up in an oxidation state of -1 to more obscure shit like molybdenum oxygen acids tending to condensate in a tetrahedral structure. If it's just school shit dig through what you've been talking about in class, if you're preparing for an anorganic chemistry exam have fun digging through a 700 page book investing more time than it takes to learn a language.

[Anonymous No.10274616]

>>10263327

I'm thinking about switching to a new major. I love biomedical engineering and here are my options.

1. BME bachelors and 1 Year Masters (pre-med)
2. Computer systems engineering and bme masters
3. electrical engineering bach and BME amsters
4. Mech E bach and BME masters
5. Software Engineering bachelors and BME masters

The reason I am considered CSE, EE, And SWE is because my dad said he could help me find a job/internship right after college.

How do I learn more info about these jobs? I want to know what I am getting myself into after.

[Anonymous No.10274619]

>>10274604
Right, but why the questions thread?

[Anonymous No.10274643]

Anyone got any resources or tips on how to solve circuits with an op-amp? I checked out some of the books from the wiki but they go over my head pretty quickly and seem to be above my level. I'm especially struggling with positive feedback.

[El Arcón No.10274665]

>>10274619
I have wondered if this horribly painful "stone in shoe" implant in my left foot was an orthotic device by which some third party thought they would drill my bones to makes my legs more even, likely having to do with Helene's anally inflicted abdominal trauma, even though a stint implanted into my bone (instead of worn in footwear) will make the root source of the issue permanently uneven, and I don't like it. If it hurt any more I wouldn't be able to walk. I wonder now if my assessment of the device in my foot was too oprimistic, and it is actually a drilling screw splitting my heel bone such that I will be incapacitated when I am unable to walk to the store to steal food. It really hurts, and if it hurt any worse I wouldn't be able to walk on it. This is in my right foot, the implant in the left foot is just an electrical zapper that someone put there, NXIVM allegedly, in my left foot.

[El Arcón No.10274677]

>>10274426
check out "N" and H again

[El Arcón No.10274714]

>>10274665
familiar looking curve

[El Arcón No.10274733]

>>10274714

[Anonymous No.10274736]

I want to write a function that calculates probability for given input where the inputs would be in the range of 1 to 20 and the sum of all outputs would add up to a certain value, what would I be looking for to learn more about how to come up with such a function? I'm not asking to be spoonfed just what concept I'm looking for.

[Anonymous No.10274755]

What are the pros and cons, generally speaking, of doing a PhD in the US and in Europe?

[Anonymous No.10274756]

>>10270612
https://www.amazon.com/dp/B0732TBPJW/ref=cm_sw_r_tw_dp_U_x_rwMmCb89FBR73
this will do. There's an EQ mount alternative for a bit more money, not a good idea considering how little this is. This is the absolute cheapest decent scope you will ever find, ideal for beginners.

[Anonymous No.10274775]

>>10274643
Positive feedback is rarely used, as it will cause the op-amp to saturate.

With negative feedback, you assert that the voltage at the inverting input is equal to the voltage at the non-inverting input. An ideal op-amp with negative feedback will produce an output voltage which causes this condition to be true.

From there, it's just Ohm's law and Kirchhoff's laws.

So in your picture, you have
vp=v2*rg/(r2+rg)
vm=(vout*r1+v1*rf)/(r1+rf)
=> vout=(vm*(r1+rf)-v1*rf)/r1
vm=vp
=> vout= (vp*(r1+rf)-v1*rf)/r1
= (v2*rg*(r1+rf)/(r2+rg)-v1*rf)/r1
= v2*(rg/r1)*(r1+rf)/(r2+rg)-v1*(rf/r1)

[Anonymous No.10275519]

Can a man pee and cum at the same time?

[Anonymous No.10275566]

Are there any career fields worth pursuing if you can't afford college?

[Anonymous No.10275635]

>>10274554
Thank you

[Anonymous No.10275738]

I'm going to be studying entry level University physics in twelve months, but I haven't studied in the last five years, I'm doing a bridging course in IT to get to in, but I know I'll need to do a lot of catching up on math and science if I want to do well. Recommended reading?

Tl:dr study material to prepare a 23 year old for uni level physics

[Anonymous No.10275742]

>>10264988
>no matter how autistic you are someone will always be more autistic than you
this is unfortunately not true because of time and geographic constraints and the rarity of the traits necessary to surpass people who reach this point of desperation in autism levels

[Anonymous No.10275766]

>>10274665
based and redpilled

[Anonymous No.10275863]

>>10275738
Interested in this. Am a math student wanting to get an education on theoretical physics. What's the reading list?

[Anonymous No.10275937]

x̂ ŷ x̄ ȳ

[Anonymous No.10275940]

±

[Anonymous No.10275953]

>>10275738
>I'm going to be studying entry level University physics in twelve months, but I haven't studied in the last five years,
>but I know I'll need to do a lot of catching up on math and science if I want to do well. Recommended reading?

Freshman science courses assume absolutely nothing from high school science classes (they're so varied they can't expect anything from them) so you're fine on that point.
Brush up on your precalculus with Khan Academy or read Simmons' Precalculus Mathematics in a Nutshell or Lang's Basic Mathematics. Then study/review some calculus.

>I'm doing a bridging course in IT to get to in,

Huh? Is that some community college associate degree? Are you majoring in IT and taking physics for fun?

>>10275863
http://4chan-science.wikia.com/wiki/Physics_Textbook_Recommendations

[Anonymous No.10275961]

>>10274616
>5. Software Engineering bachelors
Garbage
>2. Computer systems engineering and BME masters
>3. Electrical engineering bach and BME masters
>4. Mech E bach and BME masters
Are you interested in medical devices(2,3) or medical machines(4)?

[Anonymous No.10275964]

>Teaching myself math for uni
>Get a question that I can easily figure out in a few seconds
>Keep hesitating because I assume I'm wrong

Why does this keep happening? I'll be right in the end, but hesitate to answer because I assume I'm wrong. Is it just poor self esteem? When I had a math tutor in high school, he said most of my problem was having no belief in myself.

How do I get over this?

[Anonymous No.10275965]

>>10263327
How 2 get smartz

[Anonymous No.10275972]

>>10274327
>I fucked around and got an F in calc and C+ in chem but I did alot better in these classes in uni but I still have to report them which would kill my science gpa.
From what I can gather, they count but they look at them separately so it might not be a death nail.
https://www.prospectivedoctor.com/premed-myths/
https://forums.studentdoctor.net/threads/bad-gpa-from-college-courses-taken-in-high-school-suggestions-questions.632373/

[Anonymous No.10275984]

>>10275964
Meet some CS majors and see how fucking retarded they are in.

[Anonymous No.10275985]

>>10275965

[Anonymous No.10276026]

How do I count the number of basis functions in a B3LYP/6-31G* optimization? For N2O for example

[Anonymous No.10276034]

Where do I find data for sun's energy hitting Earth in watts/m2 for all geographical locations?
I heard in Britain it's around 110W/m2 which is quite different from the ideal value (1000W/m2)

[El Arcón No.10276082]

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[Anonymous No.10276323]

>>10275953
its tafe (very similar to community college) and its just a 9 month course to get a diploma, only really doing it because doing some kind of recent course is a prerequisite for any uni in my area

[Anonymous No.10276424]

why is the space complexity of a tree-recursive process O(n)?

namely the naive recursive fibo(n)?


moreover why do we seemingly disregard stack frame size when determining space complexity?
what is the cash value of space complexity metric if it assumes a seemingly infinite stack frame?

any recommendations for /well-motivated/ introductions to space complexity?

[Anonymous No.10276440]

>>10276034
>I heard in Britain it's around 110W/m2 which is quite different from the ideal value (1000W/m2)

Because of cloudiness and rain. That value is an average.

[Anonymous No.10276467]

>>10276424
>why is the space complexity of a tree-recursive process O(n)?
>namely the naive recursive fibo(n)?
Clearly it's the maximum length of sub calls (aka the height of the tree) you need to save on the stack. I.E. n -> n-1 -> n-2 .... -> 1 which is n frames
>moreover why do we seemingly disregard stack frame size when determining space complexity?
Because it's constant and big Oh throws out constants.
>any recommendations for /well-motivated/ introductions to space complexity?
Just don't be a brainlet aka a cs major.

[Anonymous No.10276496]

>>10274755
Pros of PhD in US:
>it's much longer, so you actually get more time to learn the subject, and you will get much more done
>better paid than EU

Cons of PhD in US
>most times you are a complete slave, have to TA a lot, maybe teach
>it is extremely long (6-7 years average)
>have to deal with a lot of dumbasses

Because of low entry reqs to the universities in the US and because of general ed reqs, undergrads aren't passionate usually, just want to get a good grade while doing the least amount of work, and most of the times they are hopelessly stupid.

Pros of EU
>more diversity and culture, and not of the bad kind
>average PhD lasts 3 years, 4 years maximum
>No or very low TA reqs, usually "opt in"
>less dumbasses to deal with

Undergrads in EU tend to choose their subject and not do any other classes but in their subject, so they tend to be more passionate about it. Also exams tend to be pretty hard so they tend to brainlet filter people out.

Cons of EU
>High cost of living and low wages, especially in the cities
>You have to work a lot more to catch up in those 3 years

[Anonymous No.10276521]

>>10275863>>10275738

For starters, field theory is essential to understand electromagnetism (and hence electroweak/ strong forces), so you need, for example, Field theory by Roman. Measure theory by Halmos is also crucial. You won't go far in physics if you don't understand measurements.

In physics, one usually studies the invariants of space-time and its geometry, like (classically) Galilean transformations, and more recently, Lorentzian transformations. Mumford's Geometric invariant theory is a classic.

Most of the current research in high energy physics is in string theory. As such, the book Jewels of stringology by Crochemore/Rytter will get you up to speed.

And you may laugh, but physics has become rather segregated (in light of recent events) between men and women, and as such I think it would be useful in your physics education to learn about your privilege. Fulton/Harris' book on Representation theory does the job.

[Anonymous No.10276523]

>>10276424
> why is the space complexity of a tree-recursive process O(n)?
> namely the naive recursive fibo(n)?
Because fib(n) calls fib(n-1) which calls fib(n-2) ... down to fib(1), at which point the size of the stack is O(n).

Operations on a balanced tree generally have O(log(n)) stack size, where n is the number of nodes in the tree.

> moreover why do we seemingly disregard stack frame size when determining space complexity?
Because it's a constant factor, which is a property of the implementation rather than the algorithm.

Also: if you consider the case where you're using arbitrary-size integers (bignums), the space complexity of naive recursive fib() is O(n*log(n)) as the size of the integers stored on the stack is O(log(n)). Although a naive recursive fib() with n>2^32 isn't going to complete in any reasonable amount of time.

[Aŋonymous No.10276845]

hello im retarded


can anyone tell me where does that 9 come from?

[Anonymous No.10276855]

>>10276845
8 + 1

[Anonymous No.10276856]

>>10276845
[math]8 \sqrt{3} + \sqrt{3}=9 \sqrt{3}[/math].

[Anonymous No.10276870]

>>10276856
nice spoonfeeding faggot

[Aŋonymous No.10277014]

>>10276856
thanks anon

>>10276870
not at all
what's the point of helping someone if you don't explain or hint anything

[Anonymous No.10277198]

Is counting just approximating since there is an infinite number of reals between 2 natural numbers? (is that last part even a valid assumption?)

[Anonymous No.10277371]

>>10277198
what do you mean by counting, brainlet?

[Anonymous No.10277418]

>>10277371
...um...so...could you count with reals the same way you count with natural numbers? I don't even know what I am asking anymore.

[Anonymous No.10277419]

Isn't P-Adic Analysis and Non-Archimedean Analysis the same? (I am new to the field, so i don't know much about p-adic numbers yet)

[Anonymous No.10277456]

>>10277418
yes... yes. that precise confusion was going on in the late 1800s. what does counting even mean? how many numbers are there?
answer: too many to count. literally
let's call the natural numbers (ie 1, 2, 3, 4,...) the counting numbers, since you can count things in a set by finding a 1-to-1 correspondence with a subset of the counting numbers. For example, the set {a,b,c,d} has 4 things because there is a correspondence with the set {1,2,3,4}. Now the tricky part is with infinite sets. What about the set, say, {1, -1, 2, -2, 3, -3,...} of counting numbers and their negatives. you might a priori think this set has more elements, but actually you can find a correspondence with the counting numbers, by counting in the following way
1 is 1
-1 is 2
2 is 3
-2 is 4
3 is 5
-3 is 6
etc
there is a 1-to-1 correspondence between the sets, so in fact, they have the same size after all!

the magic happens when cantor discovered that the set of real numbers (that is, the numbers on the number line, including fractions and things like pi) cannot be counted in this way by means of his diagonal argument which is not too hard to understand, but it's better if you search online for it!!

[Anonymous No.10277491]

>>10277456
Thank you. I will look the the rest up.

[Anonymous No.10277514]

help an elementary geometry brainlet out

[Anonymous No.10277529]

>>10277198
No and yes respectively.
>>10277514
It's just Pythagoras.

[Anonymous No.10277597]

>>10277529
So i know that OA.OB will always be constant for any chord drawn through a fixed point O but how do i prove that AC^2 + BD^2 will be a constant value. Does thinking of the fixed point as a center to another circle which rotates with perpendicular radii help in the bottom of the pic? It does help in seeing how if one chord gets shorter the other will get longer but how do i prove the sum of squares on those chords are of constant value? Please herp

[Anonymous No.10277964]

[El Arcón No.10277967]

[El Arcón No.10277972]

[Anonymous No.10277979]

Is there some chemical reaction that results in something that resembles a fire without having oxygen reacting with the fuel. (nuclear reactions excluded)

[El Arcón No.10277997]

[El Arcón No.10278003]

[El Arcón No.10278005]

[Anonymous No.10278244]

>>10277979
Sodium with water senpai

[Anonymous No.10278252]

>>10277979
https://www.youtube.com/watch?v=dAhiqGZCwNQ

[Anonymous No.10278323]

am i brainlet if I can think better after smoking a bowl

[Anonymous No.10278379]

>>10276467
>dont be a cs major
even if i were,
>>>>300k starting

>>10276523

hey thanks a lot, this made me realize that i was more shakey on evaluation order than anything else...

my intuitive hang up was the idea:

fibo(n) -->
fibo(fibo(n-1) + fibo(n-2)) -->
fibo(fibo(fibo(n-2) + fibo(n-3)) + fibo(fibo(n-3) + fibo(n-4))) -->
...

each evalutation of the arguments being carried out simultaneously such that all arguments after being evaluated one time yielded the next stack frame.
i dont know if this could be refined into a valid evaluation rule, but assuming it could, fibo(n) would have O(n) stack frames with each frame being O(exp(n)) in length...
the time complexity would be O(n).

hmm... i assume this is the motivation for parrallel processing

in any case im making my way.

[Anonymous No.10278556]

If I take blood from another part of my body and apply it to a part that didn't heal correctly will it fix it?
About to have dry socket

[El Arcón No.10278582]

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[Anonymous No.10278650]

>>10278586
physicists are worse than cab drivers

[El Arcón No.10278652]

[Anonymous No.10278654]

>it's schizo time

[El Arcón No.10278657]

[El Arcón No.10278668]

[El Arcón No.10278673]

[El Arcón No.10278682]

[El Arcón No.10278686]

>>10278682
Nice

[Anonymous No.10278826]

Does this makes sense?

[math]
\underline{I} = j \omega C \underline{V} \\
I = j \omega C V \\
I^2 = -\omega C V^2\\

\text{with \underline{I} and \underline{V} complex numbers with I and V as their magnitude }[\math]

like going from an equality between complex numbers and an equality between their magnitudes?

[Anonymous No.10278831]

Does this makes sense?

[math]
\underline{I} = j \omega C \underline{V} \\
I = j \omega C V \\
I^2 = -\omega C V^2\\

\text{with \underline{I} and \underline{V} complex numbers with I and V as their magnitude }[/math]

like going from an equality between complex numbers and an equality between their magnitudes?

[Anonymous No.10278842]

Hello there
So if I put my hand out while on moving car, my hand experiences a force.
Is this because of
1) Collision of air molecules and my hand, that is momentum exchange between the two
2) My hands are stopping the air flow making pressure in front of air to be stagnation pressure and pressure behind my hand is the usual static pressure.
Which explanation is correct?
Thank you

[Anonymous No.10278846]

>>10278831
If the underline means complex conjugate and the square the magnitude squared, and the frequency and capacitance are real, I think it's missing a minus in the first one because j is complex

[Anonymous No.10278849]

>>10278842
I think both are equivalent, if there are more molecules colliding with the hand, there's more pressure, that's the definition

[Anonymous No.10278886]

Can someone tell me how to prove this equation?
So far I am able to prove that
c * gcd(a, b) = gcd(ca, cb)
a = mx, b = nx
c * gcd(mx, nx) = c * x = gcd(cmx, cnx) = c * x
How do I prove that the LHS will always be smaller or equal to RHS?

[Anonymous No.10279011]

where to get textbooks?

[Anonymous No.10279012]

>>10279011
libgen.io
>>>/wsr/ if it isn't there.

[Anonymous No.10279013]

>>10279011
libgen.io

[Anonymous No.10279016]

>>10279012
ty

[Anonymous No.10279020]

How do you detect if your foot is broken?
If it's been hurting for over a week and there's little to no swelling?
What if you can use it but it hurts. Does that mean it's broken or what?

[Anonymous No.10279025]

>>10279020
Go to a doctor.
I broke my ligaments once and it didn't swell or anything, walking just hurt a lot.

[Anonymous No.10279098]

Does skin friction coefficient change from point to point of an aerofoil?
Also does normal/axial forces on an airfoil depend on angle of attack?

[El Arcón No.10279189]

>>10279011
just change the numbers, they will all be there in a few minutes:
>http://2occatl.net/img2019/MCM-book/TIMESAND___general-relevance-MCM-(48of48).png
>http://2occatl.net/img2019/MCM-book/TIMESAND___general-relevance-MCM-(47of48).png
>etc...

[Anonymous No.10279287]

>>10279025
Does it mean you have to be operated on?

[Anonymous No.10279300]

>>10279287
Nah, my leg just went on a cast for a month.

[Anonymous No.10279302]

>>10279300
a month...

[Anonymous No.10279355]

Where is /med/ general?

[Anonymous No.10279356]

>>10279355
>Where is /med/ general?
There isn't one up right now.
Feel free to make it.

[Anonymous No.10279369]

What's the term for the scientific study on how food items perish under certain conditions?

I want to learn more about to best preserve bottled food, you know, keep it cool, keep it air sealed, keep it out of sunlight.

>pic related tomat

[Anonymous No.10279387]

Can someone tell me how to do this step by step?
I know its by dividing and multiplying but i cant work it out..

[Anonymous No.10279426]

>>10279387
We divide both sides by [math]\Delta T[/math] to obtain [math]\frac{\Phi}{\Delta T}= \lambda \frac{1}{d} A[/math].
Then we multiply both by d to obtain [math]\frac{\Phi d}{\Delta T}=\lambda A[/math].
Finally, we divide both sides by A and get the result in the picture.

[Anonymous No.10279430]

>>10279426
oh man,, thanks!

[Anonymous No.10279458]

When people talk about global warming/climate change, I ask what causes it. And people say it's that there's too much carbon in the air, and they need to solve that with taxes.
When I instead say we should invest in technology that can remove the carbon from the air, people just get mad at me and can't give me a straight answer as to why that's not a good answer, beyond 'we can't know its effects'. As if we can't correct for what comes next afterwards if we can correct for the first problem.

So why CAN'T we just take the carbon out of the equation? Why is it always taxes that seem to be the answer we recieve to solve this problem?

And what exactly, in a lobbyist environment, makes people think that the factories and big spenders won't just lobby for exemptions and the tax does all of nothing but take money from normal people?

[Anonymous No.10279493]

>>10279458

https://www.youtube.com/watch?v=Mb_8DJF6Hp0

[Anonymous No.10279508]

>>10279458
Because liberals don't want just the environment, they want to push the whole social democrat agenda along with it.

[Anonymous No.10279933]

>>10279508
You haven't tried living in such a country. It's so comfy desu

[Anonymous No.10279959]

[Anonymous No.10280744]

Moderate brainlet here. How would I solve something like "At 285 mph, how long does it take to travel 114 miles?" with no paper or calculator very quickly? Are there any tricks that will get a decent approximation?

[Anonymous No.10280761]

>>10280744
Subtract 114 as many times as you can and guess the remaining percentage.

[Anonymous No.10280788]

>>10263327
If a copper wire is expose to the ocean would the EC create a current in the wire?

[Anonymous No.10280934]

What the philosophical or technical reasoning behind needing to say that a confidence interval does not have an X% chance of containing the parameter, but rather X% of all intervals made this way would contain it? I get the distinction, but wish to know how this was derived.

[Anonymous No.10281044]

>>10280744
It's a simple division problem. You set up a proportion:
x/144 = 1/285.
Then you multiply both sides by 144 and you get:
x = 144/285,
which is indeed a division problem, like I said. Getting a good estimate of the solution depends on how good you're at doing Long Division in your head without paper or calculator.
In this particular case, since 144 is smaller than 285, we know that the first digit of the quotient is zero, so it will surely take less than one hour (since the x measures time in hours). You get 144 itself as a remainder and you multiply it by ten to keep dividing and so you get 1440/285. Now how do you solve this division problem? You have to guess which number multiplied by 285 will get as close as possible to 1440 without exceeding it. Since 200*7 = 1400 you know almost for sure that the number you're looking for is less than 7, because 285 is greater than 200 and thus 285*7 will exceed 1400 and surely will also exceed 1440 (indeed 285*7 = 1995). So you must pick a number less than 7. 200*6 = 1200 so 6 might seem like a promising number, but 285 is greater than 200 and closer to 300 and 300*6 = 1800, which is greater than 1440. So 6 is no good either. 200*5 = 1000 and 300*5 = 1500. Now 1500 exceeds 1440 only by a small number ("small" relative to the size of 285) so it is probable that since 285 is smaller than 300 then 5 might be the muber you're looking for. Notice that until now we only employed multiplication of single-digit numbers that are easy to carry out in your head (200*6, for example, can be written 2*6*100; so you're just multiplying 2 by 6 and then you add two zeros in order to multiply by 100). Now that we have found a number that is likely to be the number we were looking for (number 5), you carry out the multiplication by 285 in order to verify whether it works or not. You get 285*5 = 1425 and if you add 285 you get 1710; so 285*5 is smaller than 1440 but 285*6 is larger; so 5 is the number you needed.

[Anonymous No.10281072]

>>10281044
(continued)
So as a first approximation you get x = 0.5, since we found out that zero was the first digit of the quotient and 5 was the first digit after the decimal point (which we found by multiplying 144 by 10 and then dividing by 285). But you don't know yet whether 0.5 is actually a good approximation because you need to find out the second digit after the decimal point in order to know whether you have to round up the 5. If, for example, the second decimal digit were seven, then you would have x = 0.57 which rounds up to x = 0.6. So in oprder to find out the next digit you take the remainder of the previous division, you multiply it by ten, and carry out the division. In our case, the remainder of 1440/285 is found by subtracting 285*5 from 1440:
1440 - 285*5 = 15.
So you take 15 and you multi8ply it by 10 and you get 150. 150/285 gives a quotient of zero since 150 is less than 285. So you have x = 0.50, which rounds down to x = 0.5; therefore 0.5 is your correct answer which is accurate to the first decimal place. Since x measured time in hours, you have that it takes approximately 0.5 hours to travel 144 miles at 285 mph, so about thirty minutes.

[Anonymous No.10281230]

>>10280744
>>10281044
>>10281072
Or maybe you see that half of 285 is 142.5, and so the error of calling 144/285 roughly 1/2 is less than one in one hundred.

[Anonymous No.10281253]

>>10280934
the first would imply you know something about the true nature of the value you want to estimate, which is a big claim.

The second only depends on the method you use to estimate the value, and you know what method you used

[El Arcón No.10281374]

[El Arcón No.10281377]

[El Arcón No.10281384]

[Anonymous No.10281394]

>>10279189
Very good taste.

[Anonymous No.10281408]

there is no 52nd mersenne prime.

proof:
clearly, it is not the case that if p (there is no 52nd mersenne prime), then not p.
therefore it must be the case that p and not not p.
p and p.
p.
there is not 52nd mersenne prime.

QED


what is wrong with this proof? obviously "p" could be any statement and the "proof" would work.
~(p implies ~p)
~(~p or ~p)
(p and p)
p.

[El Arcón No.10281523]

>>10281408
>what is wrong with this proof?
It is circular because it assumes P.

For an example of something non-circular, consider the definition of real numbers: A real number is a cut in the real number line. One asks: What is a number line? All lines are number lines because all lines can be cut. One asks: What is the real number line? The number line is a unique line with the label "real." One asks: What is a line? A line is a geometric object. One asks: What is geometry? Geometry is the study of shapes. One asks: What are shapes? Shapes are ideas. One asks: What is an idea? An idea is a (relatively) non-physical abstraction held in the human mind? One asks, etc...

To define real numbers, I have referred to the real number line, but then I have defined the real number line without reference to real numbers. Therefore, the definition is not circular.

[Anonymous No.10281533]

what exactly does "t. " mean

[El Arcón No.10281536]

>>10281523
it's like it's only a coincidence that the words "real number" appear in the name of the real number line

[El Arcón No.10281539]

>>10281536
yeah pretty much. You could call the real number line the "domain of all affine parameterizations" and it would come out the same.

[Anonymous No.10281541]

>>10281533
Hello friend, welcome to 4channel.
t. is like the hyphen or wave used to attribute a quote to a person or group of people. It is used ironically or to mock someone.
Why am I in this party? I need to compile my kernals
t. /g/ poster

Or say you posted something like
"Intel CPUs are better than ayyymd because..."
and someone replies with
>t. pajeet Intel shill
To make fun of you.

[Anonymous No.10281543]

>>10281541
what does the "t" explicitly stand for though?

[Anonymous No.10281546]

>>10281543
It comes from Finnish memeboards.

Basically, "t." is short for "terveisin" or "terkkuja" which translates to "greetings" or "yours truly". As if ending a letter or a postcard.

So "t. Swaglord" means essentially "Greetings (from) Swaglord."

Copied from the internets

[Anonymous No.10281548]

>>10281546
thx anon I never thought I'd actually learn something here

[Anonymous No.10281551]

>>10281548
There are many other things actually worth learning :)
Don't spend too much time here

[Anonymous No.10281575]

>>10281523
>it assumes the conclusion
clearly
im just hoping that someone can shed light on the more formally (or perhaps philosophyically) logical problem with using material conditionals in proofs... or perhaps about the appropriateness of using the law of excluded middle (ie constructivism and its discontents)

that it is not the case that some proposition being true would imply that same propositions negation seems to me like a very reasonable thing to assume.

>>10281536
>coincidence
accident

[Anonymous No.10281590]

>>10281408
Second line, therefore.
El Arcon is essentially right.

[Anonymous No.10281626]

>>10281590
>right
>smugvietnamesskrimshawchild.jpg
yes he is essentially right.

[Anonymous No.10281637]

>>10281626
Well, he's shitposting, but he was right that the problem was anon assuming the conclusion. That's what the "essentially" meant.

[Anonymous No.10281783]

>>10280744
the exact answer would be 114/285 of an hour
it's about half an hour as you can see
if you need to be more precise, you can kinda see that 114/142.5 is 80% (subtract 14 or 15 twice from 142.5 to get pretty close), so subtract 6 from 30 minutes twice to get 24 minutes

[Anonymous No.10281790]

>>10281783
>so subtract 6 from 30 minutes twice to get 24 minutes
meant subtract 3 from 30 minutes twice (analogous to subtracting 14 or 15 twice from 142.5) to get 24 minutes

[Anonymous No.10281991]

brainlet here : i got a really stupid question that has been bothering me for a while.

How much decibel will it take for a certain sound to be audible all over the corner of world/ how much power will it take to generate said voice ?

[Anonymous No.10282023]

Why are sine waves the commonly used fundamental waves? Is it simply a matter of convince since they are simple, or is there some deeper connection in nature that favours sine waves?

[Anonymous No.10282064]

>>10282023
they're the simplest and you can construct any signal by adding up sine waves

[Anonymous No.10282131]

What would happen to a computer that is aware of its functioning? (refer to [math]\pi[/math] (1998), Darren Aronofsky)

Not implying computer/brain analogy. Just curious.

[Anonymous No.10282149]

>>10282064
It's beautiful.

[Anonymous No.10282156]

>>10282064
How does one even design something like this

[Anonymous No.10282171]

im stuck trying to figure something with error bounds in alternating series.

So you got
|S - S_N| <= a_n+1

but it can also be smaller than a_n+2 right? and in that case you can be wrong with what term you need.

i cant get passed this without realizing if that is the case or not.

[Anonymous No.10282278]

The vectors (3a-b) and (a+4b) are perpendicular, and
|a|= 3|b|.
Determine the angle between a and b.


The answer is cos -22/33. Please help this online course doesn't explain anything. If you know a website with these kinds of problems that could help.

[Anonymous No.10282475]

Can someone help me identify the name of a effect in impure crystals? I was given the choice to choose my thesis but I cant seem to find the name of the effect. I think its called Kondor Effect but its likely that its wrong. Its about the behavior of a lattice with impurities/defects which will, if correctly constructed not behave like a crystal with impurities but like a normal one. The Kondor effect is supposed to additionally play a part in the spin flip of a electron of host material and defect electron. If said electron e_1 where to occupy an empty bloch state of the defects and leaves said state there is a possibility for the spin of e_1 to come out the same as before. It is also possible that both e_1 and defect electron with opposite spin in same state will flip twice thus changing nothing. There are possibilities for 3,4, etc.. spin flips thus the spin of e_1 can also be different from before.

[Anonymous No.10282535]

How do I find theta if I know cos^2 theta?

[Anonymous No.10282536]

>>10282278
[eqn] \vec a \cdot \vec b = |\vec a| \times |\vec b| \times \cos(\theta) \qquad \textrm{where theta is the angle between the vectors} \\
\vec c \cdot \vec d = 0 \qquad \textrm{when vectors c and d are perpindicular} [/eqn]

also note that the dot product is distributive, I got arccos( -23 / 33)

[El Arcón No.10282541]

When they say, "He doesn't even know basic linear algebra," what they mean is, "He doesn't know basic matrix algebra." The latter is true is because my own research deals with 1x1 objects, so the array structure of "multiplectic" objects having dimension other than one by one is not something I even gotten into the basics of. First I want to better understand the 1x1 object. Indeed, the map I use to prove the limits of sine and cosine infinity and the Riemann hypothesis' negation as corollary, essentially, of the "linear" map
y=mx+b

where we also use points further out on the real number line from the origin, numbers which can never even reach 1% of the way to infinity, specify "points in the neighborhood of infinity." The say, "These numbers can't exist because you are just using a point at the end." My rebuttal is that the line itself contains an infinite number of points. The natural numbers, and the limit of the partial sums, are compactified onto the origin because when you look at the extended real number line any natural number is less than any infinite decimal real number percentage of the way from the origin to infinity. Infinity is inherent to the real line although detractors will say, "The fact that it even mentions infinity means that it is not standard and therefore it is disqualified." This is stupid because infinity is the number of points in the real line, the pure domain of real analysis.

The likely thing, having to do with the structure of the critical strip no less, is that the line can be sent through the exponential map (wrapped around a cylinder), the the Cantor example of dilating the radius of the circle to show that circles of different sizes have unequal number of points. By increasing or decreasing the radius of the unit circle, likely according to the golden ratio, you can rescale the theory as Donatello Dolce has documented nicely.

[Anonymous No.10282550]

>>10282536
also just to clarify, the [math] \times [/math] symbols are meant to signify scalar multiplication, not the cross product

[Anonymous No.10282563]

>>10282131
destroy itself

[El Arcón No.10282879]

>>10282541
When they say, "He doesn't even know basic linear algebra," what they mean is, "He doesn't know basic matrix algebra." The latter is true because my own research deals with 1x1 objects and the array structure of "multiplectic" objects having dimension other than one by one is not something I have even gotten into the basics of (yet.) First I want to better understand the 1x1 object. Indeed, the map I use to prove the limits of sine and cosine infinity and the Riemann hypothesis' negation as corollary, essentially, is the "linear" map
y=mx+b

where we also use points further out on the real number line from the origin (numbers which can never even reach 1% of the way to infinity) to specify "points in the neighborhood of infinity." The say, "These numbers can't exist because you are just using a point at the end." My rebuttal is that the line itself contains an infinite number of points. The natural numbers are compactified onto the origin because, when you look at the extended real number line, any natural number is less than any infinite decimal real number percentage of the way from the origin to infinity. Therefore, numbers are one-point compactified at the origin and at infinity, and this year I will describe the points in between with "levels of aleph." Infinity is inherent to the real line although detractors will say, "The fact that it even mentions infinity means that it is not standard and therefore it is disqualified." This is stupid because infinity is the number of points in the real line: the pure domain of real analysis.

[El Arcón No.10282898]

I have $0.99 if someone wants to be my typo identifier for a period of 1 year. This probably isn't as much as they pay to put them in but, imo, the qwerty keyboard is going the way of the dodo.

[El Arcón No.10282903]

>>10282898
https://www.youtube.com/watch?v=q18hXaE-FpU
Here's this one time I filmed them inserting typos right before the Benghazi attack, and then the question was, "Who changed the talking points?," and, "Who made the 'anti-muslim' video?"

[El Arcón No.10282913]

Pic related in the middle there is the one who probably baited me into not getting a book deal, mocking me with her "schizo" meme. You can still buy my book any way (self-published on Amazon) but you should not think and I am not asking you to buy it. However... I do have a book and if they would acknowledge all my great research then people would buy my book, I assume, and that would instantly remedy my condition of indigence, which is the main problem in my life right now as I have refused to continue to beg for money. I choose instead to protest the economic conditions I find myself subjected to, and my research has seemingly benefited from a change in direction.

They put the scene about my book in The Equalizer 2, and the woman said, "Oh, I haven't read it and I probably never will," and that meme comes from the person in the middle there. I think it's my mother.

[El Arcón No.10282963]

>>10282903
Yeah... I really stopped caring about typos in the aftermath of the Benghazi video.

[Anonymous No.10283264]

>>10282023
> Why are sine waves the commonly used fundamental waves?
Simple harmonic motion.
[eqn]\frac {d^2x} {dt^2} = -\omega^2 x \Rightarrow x = a \, sin(\omega t + \phi)[/eqn]
where a and [math]\phi[/math] are determined by initial conditions.