/sqt/ /qtddtot/ - stupid questions thread

[Anonymous No.14796587]

Previous thread >>14776276

>what is /sqt/ for?
Questions regarding math 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 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

>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
>charts?
imgur.com/a/pHfMGwE
imgur.com/a/ZZDVNk1
>tables, properties and material selection?
www.engineeringtoolbox.com
www.matweb.com

Tips for asking questions here:
>attach an image (animal images are ideal. Grab them from >>>/an/)
>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.14796638]

Unanswered questions:

Math questions:
>>14779504 [Big oof question. It's like I'm solving a test in a dream because the questions all seem reasonable but they're all nonsense]
>>14779845
>>14780254
>>14780574

Physics questions:
>>14776304
>>14794958

Chemistry questions:
>>14796369
>>14796570

Stupid questions:
>>14776339
>>14778017 [Yes]
>>14777884
>>14778542
>>14782825
>>14783501
>>14783605
>>14783784
>>14786608 [Centrifugal force]
>>14791771
>>14794111
>>14794189
>>14795056
>>14795081

[Anonymous No.14796743]

>>14780574
>Suppose there are four possible events whose probabilities A(x,y), B(x,y), C(x,y) and D(x,y) depend on the two variables x and y.

[Anonymous No.14796786]

Wow no one replied to their question. >>14783605

[Anonymous No.14796889]

Do you guys use/recommend any software to check for self-plagiarism?

[Doctor Eli Selig !!JQHA6kqyl91 No.14797107]

>>14796587
Good evening /sci/entists.

I have returned from the Dra/g/on Maid board to ask for help playing science. Does anyone know of a list of cool math or science problems I can try to solve with my stack language? Last thread I got to play computer science with INFLATING Maid Books and it was a lot of fun.

SLAM is for non-deterministic programming. So examples that benefit from randomness would be cool.

If I can find some interesting things to solve then I will include them as demo programs when I release my book/interpreter (it will be all CC0).

Also if you like using your computer to play science do you like REPL environments? I know the LISP dra/g/ons like them and after building one of my own I'm kind of sold on the concept because interactive programming is fun. I think because you can really see and feel your progress as you put stuff into the REPL.

[Anonymous No.14797126]

>>14796743
I probably should have put that in stupid but my brain filtered everything he wrote and replaced it with "[math]A, B[/math] and random variables, does the event [math]A = B[/math] have a name?"

[Anonymous No.14797144]

R = {〈x, y〉|x + y ≤3, x ∈A, y ∈A },
A = {1, 2, ..., 10}

Is R = {<1, 1>, <1, 2>,<2, 1>} the correct interpretation?

[Anonymous No.14797375]

So I live in a third world shithole where
>coca leaves are legal
>it's cheap to buy enough coca leaves to make a few grams of cocaine
>cocaine is decriminalized if you have just a few grams and you're not selling it
So in theory, it should be legal (or rather, illegal but decriminalized) to make your own coke for personal use.

I want to make coke for myself, I don't want to turn into a drug lord
How feasible would it be to learn to make cocaine hydrochloride from the leaves?
I can buy most chemicals and passed an intro to chem class as part of my engineering degree. Math isn't really a problem if I had to learn some extra chemistry topics.

My biggest concerns are
>practical complexity of the chemical process
I only did just two lab projects as part of that class, so I'm lacking in practical experience.
>explanation of the process
I imagine it's not something you can find in books, unless you can, but then I wouldn't know what books I could read on the topic.

Any ideas?

[Anonymous No.14797410]

>>14796587
i'm gonna try to make this is as TL;DR friendly as possible: hand to God, i kinda wanna pursue a PHD in math, but it's genuinely not about the money. i truly do want to enrich humanity and i think mathematics might actually be the right way to do it. with that said, i just gotta ask:

is that "PHD in math, 300k starting" shit a meme, or am i actually gonna accidentally have a fat bank account because i've finally accepted that "there was always a reason you scored in the top 1% on all the math tests, even though you found math to be boring at the time"?

tl;dr version (i know, i know) - is "PHD in math, 300k starting" JUST a meme or is it an actual way to a fat fucking bank account, reasons/morals notwithstanding?

[Anonymous No.14797429]

>>14797410
You will get the biggest of racks if you decide to quit research and work for finance/computer science.

Most people in highly abstract, mathematical research PhD programs (such as obviously math or even theoretical physics) tend to not pursue research after doing their PhD because theory is very oversaturated right now. However, CS and finance will suck you up harder than a crackhead for a fiver.

Most based method for mathematical/theoretical people is to pursue a PhD knowing you probably will not get a research/tenure position. Do the PhD and after, maybe spend a bit of your life publishing some papers for personal fulfillment. Then, change careers and enjoy your upper middle class lifestyle being a cog in the brutal financial machine.

At least, that's my plan ;)

[Anonymous No.14797454]

>>14796587
How do get Touhou gf?

[Anonymous No.14797463]

>>14797429
well, the good news is that i have zero interest in anything theory based. dynamical systems piqued my interest.

[Anonymous No.14797477]

>>14797429
>implying the US dollar will survive the decade
You must be a moron if you're in Finance and have no doubts about the current state of affairs.

[Anonymous No.14797566]

Why does alcohol make me write longer posts?
>>14797410
>i kinda wanna pursue a PHD in math, but it's genuinely not about the money. i truly do want to enrich humanity and i think mathematics might actually be the right way to do it.
Letting reddit humanism about improving HUMANITY through SCIENCE and TECHNOLOGY actually guide your life decisions is an absolutely beyond terrible idea and I strongly urge you to reconsider, but if you're actually retarded enough to fall for it in the first place you're probably beyond saving.
Become a doctor or something. Perform surgeries, save lives, get a high on the concreteness of it all and on the smiles you've directly caused instead of jacking off in your old age about how um your solution method for semi-quasi parabolic pdes uh improved performance in uhhhhhhhhh transportation of food which let businesses raise their pri-sell better food to the disenfranchised and improve lives or something.

[Anonymous No.14797572]

What is a good problem book on one variable real analysis?

[Anonymous No.14797628]

>>14797566
>Letting reddit humanism

stopped reading there. i'm christian and it's through my religion that i'm even here in the first place. if you can't keep that in mind in future responses then you have nothing to offer me because you're not talking to ME, you're talking to your interpretation OF ME. separate the 2 and try again, or don't.

[Anonymous No.14797653]

I dropped out of college 2 years ago because I was a lazy dumbfuck with a very low gpa. I also gained a lot of debt because of that. After getting a pretty solid job, I managed to pay it all off. Now I'm feeling antsy about going back.

Should I go back despite remembering very little and still having a low gpa? I would still keep my job while attending.

[Anonymous No.14797670]

>>14797653
Spend at least a year or two grinding stuff you struggled with until you feel confident you won't have problems with stuff that dragged you down before.
If after a year of self-study you still believe you need to go to college for the sake of getting a degree, then do it. Just don't expect it to be easy.

[Anonymous No.14797681]

sorry for covid related question, but isn't the idea of professional athletes being the epitome of health a huge meme? human body isn't supposed to be under all that stress how do you draw that line between being health and performance

[Anonymous No.14797917]

>>14797566
>Perform surgeries, save lives, get a high on the concreteness of it all and on the smiles you've directly caused
>>14797429
Son, math is a life of luxury. The luxury is escaping with a clear conscience.

[Anonymous No.14797948]

>>14797670
Yeah, it's probably better if I waited until I have enough money to keep a job and go to school comfortable too.
I'm not sure if I can teach myself programming and land a programming job without a degree also.

[Anonymous No.14797969]

>>14797628
God so pitied the world that he gave them mathematics.

[Anonymous No.14798063]

Is this correct?

[Anonymous No.14798073]

>>14798063

[Anonymous No.14798124]

>>14796638
>>>14796570(Cross-thread)
small amounts (<10ml) yes. larger amounts, store in separate bottles - halogenated and nonhalognated organic solvent wastes - and bring to your nearest chemical waste disposal center.

[Anonymous No.14798149]

>>14797144
yes

[Anonymous No.14798153]

>>14798063
probably not

[Anonymous No.14798297]

Is not literally repeating what was written in a book from 70s but expanding, clarifying and updating it an act of blatant insubordination?

[Anonymous No.14798312]

>>14798297
Isn't this what pretty much every textbook does?
They all repeat results from other books or journal articles in a way that the author believes is easier to understand.

[Anonymous No.14798360]

Why are sequences denoted as [math] x_n[/math]? When I read that I think of the [math] n[/math]-th term in the sequence. My notation for sequences [math] x_{\Bbb N}[/math], and for subsequences [math] x_{j(\Bbb N)}[/math], where [math] j[/math] is an increasing function that maps the position of a term in the subsequence to the the position it has in the supersequence, is far superior and should replace the conventional notation.

[Anonymous No.14798370]

>>14798360
>When I read that I think of the n-th term in the sequence.
That's because it is. The general notation for a sequence is something like [math](x_n)_{n \in \mathbb{N}}[/math].

[Anonymous No.14798375]

could "learning" be a step function % of neurons firing, that's how we have those eureka moments

[Anonymous No.14798389]

>>14798370
The most common notation is [math] \{x_n\}[/math], which still has the same problem.

[Anonymous No.14798427]

>>14798312

It probably has to be like this.

[Anonymous No.14798477]

>>14797628
>his brain just translates "reddit humanism" to "reddit atheism"
Go be illiterate somewhere else, this board is for people who can read.

[Anonymous No.14798493]

I'm stuck on a simultaneous equation.

>>>/wsr/1253571

Not looking for the solution but the way to approach this one.

[Anonymous No.14798496]

>>14798493
Gaussian Elimination

[Anonymous No.14798510]

>>14798496
Thanks, I'll look into it.

Weird if that's the way to deal with this because the text book I got this from doesn't teach matrix algebra.

[Anonymous No.14798592]

>>14798510
Usually you learn how to apply Gaussian elimination without explicitly using matrices in middle school, but it's still Gaussian elimination.

Just google "how to solve linear systems of equations" and the middle school version will probably show up somewhere.

[Anonymous No.14798612]

https://www.youtube.com/watch?v=p_8yK2kmxoo

Why would strange matter be so stable if strange quarks normally decay in less than a nanosecond?

[Anonymous No.14798645]

>>14797566
>>14798477
>touhou pictures

i just noticed and cringed hard; i didn't realize i was addressing a limp dicked, tourist retard who accidentally happened here. nvm, feel free to keep embarrassing yourself while being useless.

[Anonymous No.14798647]

>>14797566
>>14798477
>touhou pictures
>t.

i just noticed and cringed hard; i didn't realize i was addressing a limp dicked, tourist retard who accidentally happened here. nvm, feel free to keep embarrassing yourself while being useless.

[Anonymous No.14798669]

>>14798647
What's a touhou? Does it have maids in it?

[Anonymous No.14798678]

>>14798669
a shmup (shoot em up) game that retards like the one ITT are too slow and stupid to actually play but pathetic and genetically defective enough to worship the waifu it gave them.

[Anonymous No.14798729]

>>14796587
I want to do a living by researching mathematics, doing theorems and discovering/inventing math because i find it real fun. Is it feasible? Do I need to go to a top university to achieve this?

[Anonymous No.14798768]

>>14798729
You would need to either be financially self-sufficient or work somewhere that would allow you the time to do that, something that had no immediate tangible benefits. So realistically you are going to have to work in academia but it doesn't have to be a top university.

[Anonymous No.14798799]

>>14796587
Hey, how much do changes in atmospheric air pressure, change the boiling point of caffeine?
I want to make tea extract rich in theine/caffeine and I heard some people failed at doing just that, and it's supposed to be as simple as boiling tea water

[Anonymous No.14798823]

>>14798799

[Anonymous No.14799085]

Define a relation on Z as xRy if abs(x-y) < 1. What familiar relation is this?

Book of proof ch 11.2 Q8

I tried to plot it and I put it in Wolfram alpha but I don't see anything useful or familiar with this relation. Is it like a floor function or something?

Also what does it mean to define the relation, isn't it already defined just from that description? R = {(x,y) e Z | abs(x-y) < 1} ?

[Anonymous No.14799122]

>>14799085
>what does it mean to define the relation, isn't it already defined?
you're correct, the relation is defined the way that it's specified. It's not asking you to do anything in the in the first sentence it's just setting up for the question.

notice that you are only looking at the integers, if you pick some integer (say 5) and answer "what integers is 5 related to?" it should be pretty clear what the relation is.

Also don't just answer the question but make sure that you are explicitly proving it.

[Anonymous No.14799204]

>>14799122
Ty anon

Is it the equality relation? If I pick x = 5 then y can be 5.99 or 4.01 if it was real but since it's integer it would get rounded to 5 right?

I'm not sure how to prove them though

[Anonymous No.14799233]

>>14796587
Would you be able to teach an autist how to interact properly by showing them brain scans of normal people interactions and then teaching them so that their own brain lights up in the same categories?

Could this same technology be applied to other fields? Mathematicians can seem like wizards to people, but that could be because they literally don't know how to think the way they do. I think that there has to be a way to demonstrate mental processes the way you can demonstrate physical processes. Is there a better way to do so, using existing technology, aside from brain scans? I find that in many instructional books the description of the act of thinking is very sparse compared to other processes.

[Anonymous No.14799298]

why -(-2) is 2?

[Anonymous No.14799352]

>>14799298
Maybe -(-2) = (-1)*((-1)*2))= (-1)*(-1)(2)=(-1*-1)*2 = (1)*2 =2

Does this count as a proof?

[Anonymous No.14799369]

>>14799298
Axioms used: Associativity, existence of additive inverse, existence of additive identity.
[eqn] -(-a) + (-a) = 0 \\ \iff -(-a) + (-a) + a = a \\ \iff -(-a) + 0 = a[/eqn]

[Anonymous No.14799383]

>>14799233
>Would you be able to teach an autist how to interact properly by showing them brain scans of normal people interactions and then teaching them so that their own brain lights up in the same categories?
Fairly sure some autists can mimic and mechanically copy how normal people act, but I don't exactly quiz people I meet if they are on the spectrum and if that's why they're avoiding eye contact and alternating between staring at the floor and the ceiling.
>I find that in many instructional books the description of the act of thinking is very sparse compared to other processes.
There are a bunch of books in mathematics about methods for proving statements and solving problems.
When teaching integration or how to analytically solve ODEs books usually go:
>active pattern-recognizing monkey brain to see if you recognize anything in the problem
>if so, utilize that to simplify the problem
>otherwise try method I
>repeat step 1
>move on to method 2
and so on and so forth.

[Anonymous No.14799444]

>>14799383
>alternating between staring at the floor and the ceiling.
lol, i totally do that shit

[Anonymous No.14799634]

>>14799444
Unironically just start wearing sunglasses indoors so I can't see that you're actually staring at the floor while talking.

[Anonymous No.14799719]

This is a long shot.

When I was 18 I abused a lot amphetamines. I've always had a bad habit of tensing up my jaw muscles and jutting out my chin, but I'd do this excessively when high. At some point I noticed I have a popping jaw on my left side. It always feels tense. If I eat it will often pop. It will pop at will. Sometimes by the end of the day my jaw will feel sore. I have been living like this for seven years. What do you think it is? Is there a way to fix this without an intervention?
>>14799298
Think of it as negative two times negative one. One because -(-2) can be written as -1(-2) or -1*-2. I just like to think of it as negative X times negative.

[Anonymous No.14799840]

if liquids flow from higher pressure to lower pressure how come the deeper water in the ocean doesn't flow upwards?

[Anonymous No.14799884]

>>14799840
The ocean is at equilibrium. The higher pressure down below is simply due to the weight of the water above.

[Anonymous No.14800461]

Can some math-physics anon help me understand what this problem is asking me to do? I'm an engineer sorry

[Anonymous No.14800464]

>>14800461
This is the solution

[Anonymous No.14800482]

>>14800461
>>14800464
Which part don't you understand?

[Anonymous No.14800708]

Regarding the dual slit experiment: I see the interference pattern and understand the (simplified) explanation well enough. What I don't get is why the two slits become point sources for light just because light passes through them. With water ripples, I can see how the pressure transmitted by the medium would allow a ripple to spread out (radiate) from a hole as water passes through. But with light, it's not a material flow. What's happening to the light at the slot that causes it to spread in all directions from that point? Is pic related a poor representation?

[Anonymous No.14800739]

>>14800482
Where does the "solution" come from? Why the cross product? What does divided by T>inf mean, its the first time i hear of it, i knew of X limit to infinity, but not divided by, what and why k equal r are remaining terms? Pretty much everything, sorry. I'm not used to dealing with this type of problems

[Anonymous No.14800761]

>>14800739
>Why the cross product?
It's not a cross product, it's a normal product. He means the cross terms (like how in [math](a + b)^2[/math] the only 'crossed' term is [math]2ab[/math]).
>What does divided by T>inf mean
It's normal division.
>but not divided by
The division is taken before the limit.
>why k equal r are remaining terms?
It's explained in the proof. [math]e^{j (\omega_j - \omega_r) t[/math] is a periodic signal, so the integrals are bounded and the limit vanishes.
>Pretty much everything, sorry. I'm not used to dealing with this type of problems
Do you at least understand all of the definitions used?

[Anonymous No.14800809]

>>14800761
>Do you at least understand all of the definitions used?
Yes, but i still don't understand what's going on at all. Could you tell me, roughly, what steps are taken to solve this problem? So i can know what to look into.

[Anonymous No.14800991]

so if marijuana can cause psychosis what is a safe limit or do we not know yet?

[Anonymous No.14801008]

>>14800739
>>14800809
The cross product terms are when [math]k \neq r[/math], those integrals contains terms of the form [math]e^{jt}[/math]. Since this is periodic the integral will converge to a fixed value (this is a commonly used fact and a simple search for integrating trig functions over infinity bounds will explain in detail). This number is then divided by T, but in the limit T becomes infinity those terms will vanish to zero so contribute nothing to the final answer.

So you then left with the terms when [math]k = r[/math], in that case the exponential becomes [math]e^0 = 1[/math]. So the integral that is left is what is shown in the proof, which is a straight forward basic integration and gives you are factor of T. This is then cancelled by the outer 1/T term. The limit will then not chance the answer because no T terms are left, and hence you are left with the final expression.

[Anonymous No.14801012]

>>14800739
>>14800809
The cross product terms are when [math]k \neq r[/math], those integrals contains terms of the form [math]e^{jt}[/math]. Since this is periodic the integral will converge to a fixed value (this is a commonly used fact and a simple search for integrating trig functions over infinity bounds will explain in detail). This number is then divided by T, but in the limit T becomes infinity those terms will vanish to zero so contribute nothing to the final answer.

So you are then left with the terms when [math]k = r[/math], in that case the exponential becomes [math]e^0 = 1[/math]. So the integral that is left is what is shown in the proof, which is a straight forward basic integration and gives you are factor of T. This is then cancelled by the outer 1/T term. The limit will then not change the answer because no T terms are left, and hence you are left with the final expression.

[Anonymous No.14801088]

>>14801012
>>14801008
Thanks for the help

[Anonymous No.14801215]

>>14800708
> What I don't get is why the two slits become point sources for light just because light passes through them.
They don't become point sources. They are slits with a finite size.
> What's happening to the light at the slot that causes it to spread in all directions from that point?
Because it's a wave that enters each slit, it's a wave that travels through the slit, and so a wave is what leaves each slit.

[Anonymous No.14801355]

>>14797107
There's lots of exercises in Knuth's The Art of Computer Programming. It has unsolved problems too. I quite liked Volume 2 myself but I enjoy doing number theoretic algorithms the most. Number theory has a lot of unsolved problems and that book will get you started.

[Anonymous No.14802293]

Can anyone help me understand the difference between lim and lim sup/lim inf?
more specifically, I am currently reading a paper, where they define some system as weakly degenerate if
[math] \limsup_{t \to \infty} || \mu_t - \mu_0 ||_2 = \infty [/math]
and strongly degenerate if
[math] \lim_{t \to \infty} || \mu_t - \mu_0 ||_2 = \infty [/math]
with [math] \mu [/math] being some vectors that change their values over time. They say that the second function describes a system where the distance between the vectors drifts apart and stays apart.

[Anonymous No.14802375]

>>14802293
[eqn] \limsup_{t \to \infty} || \mu_t - \mu_0 ||_2 = \infty \iff (\forall K,s \in \mathbb{R}) (\exists t > s) || \mu_t - \mu_0 ||_2 > K
[/eqn]

[eqn] \lim_{t \to \infty} || \mu_t - \mu_0 ||_2 = \infty \iff (\forall K \in \mathbb{R}) (\exists s \in \mathbb{R})(\forall t > s) || \mu_t - \mu_0 ||_2 > K
[/eqn]

[Anonymous No.14802700]

>>14802375
Ohhh, I think I get it now
Thanks

[Anonymous No.14803919]

>>14796587
Ok, so I'm trying to become more productive.

What I've gathered, caffeine, similarly to cocaine, reduces the rate of which you reabsorb dopamine, causing it to linger longer than normal.

Could I, then, play video games for half an hour when I take my caffeine pill, to build up dopamine, and then go and study and enjoy the studying more?
Would this be more effective than just taking my pill and then go and study immediately?

[Anonymous No.14804090]

>>14803919
Only thing that will make you more productive in a sustainable way is: sleeping 8 hours, waking up early, exercising, followed by a protein and fat rich hearty meal and a cold shower, EVERY DAY. Don't believe me? Do it for even half a week, and you'll see the difference.

[Anonymous No.14804446]

Which one is correct bros?

1

[Anonymous No.14804458]

>>14804446
2

[Anonymous No.14804664]

>>14804446
>>14804458
1

second line of 2 is wrong

[math](2y - x)^2 \neq 4y^2 - x^2[/math]

[Anonymous No.14804694]

>>14804664
Thanks fren. You're awesome.

[Anonymous No.14805152]

Asking this one again since I never figured it out.
What would the force between the plates be in this situation? If the metal were a liquid, what would happen?

[Anonymous No.14805649]

>>14805152
It's as if the metal wasn't there. The field across the metal is zero.

[Anonymous No.14805763]

You guys can help me get the Fourier transform of pic?
I know that the transform of e^(-a|t|) is 2a/(a^2 + w^2) but this isn't the same.
I tried doing the standard e^-jwt integral but I can't solve that either.

[Anonymous No.14805805]

>>14796587
How I science and stuff???

[Anonymous No.14805994]

>>14805805
Read soience books for I luv soience bros and drink soilent

[Anonymous No.14806270]

Which branch of Physics is the one that explains why a single, unfolded paper falls slower than crumpled up ball of paper? Some guys on YouTube said it wasn't because of the Bernoulli effect.

[Anonymous No.14806277]

>>14806270
It's called friction. You learn that in middle school basic physics

[Anonymous No.14806520]

>>14806270
fluid dynamics

[Anonymous No.14806533]

I've been teaching myself about lichens recently and want to get into spot testing. I haven't done anything in a chemistry lab since I was in high school. Do I need to be careful with any of the following chemicals, and if so how can I best prepare to use them for spot testing?

>calcium hypochlorite
>iodine
>potassium hydroxide
>para-phenylenediamine

Thank you in advance and sorry for the dumb question, I just don't want to kill myself.

[Anonymous No.14806585]

>>14806533
you should google all of these chemicals followed by "sds" for safety data sheet. thermo fisher usually has good ones. they will tell you how risky everything is.

as for all of them you listed, they are all dangerous but can be handled safely with gloves and a mask to prevent accidental inhalation/ingestion. don't consume any of them obviously. don't get them on your skin, but you won't die from a skin splash like you would from some chemicals.

[Anonymous No.14806596]

>>14806585
Appreciate it.
>sds
Super useful, thanks for the tip. I'll be cautious with these.

[Anonymous No.14806603]

>>14796587
I'm 18 and I think I have covid, how will this affect my brain? How much will my IQ decrease?

[Anonymous No.14806611]

>>14806603
if you're already stupid enough to ask medical questions on 4ch I don't think it matters.

[Anonymous No.14806687]

>>14805763
e^-2πif/(π^2f^2+1)
You can either evaluate the integral directly by splitting into (-∞,1) and (1,∞), or use the transform of e^-a|t| with a=2 and the time-shift rule:
F{f(t-a)} = e^-2πiaf·F{f}
with a=1.

[Anonymous No.14806817]

Will a LED work with AC?

[Anonymous No.14807497]

How do I get good at problems like these?
Prove that for all [math]x,y,z \in \mathbb{R}[/math]

[eqn] x^4 z^2 + x^2 y^4 + y^2 z^4 \geq x y^3 z^2 + x^2 y z^3 + x^3 y^2 z[/eqn]
The solution is a short one-line proof but I couldn't find it on my own.

[Anonymous No.14807510]

Does
[eqn]
f(x) =
\begin{cases}
4-x^2, \quad &\text{for } -2 \leq x \leq 2 \\
e^{3-x}-1, \quad &\text{for } x > 1
\end{cases}
[/eqn]
have a global maximum value of [math]e^2[/math] at some [math]x[/math] in [math](1, 1.01][/math]?

[Anonymous No.14807512]

>>14807510
should be [math]-2 \leq x \leq 1[/math] for the first domain

[Anonymous No.14807531]

>>14807510
For x different from 1 the function is differentiable so you have to check fives cases.

>x with f'(x) = 0
Happens only at x=0 and f(0) = 4
>x = -2
f(-2) = 0
>x = 1
f(1) = 3
>Rightside limit at x=1
lim_{x to 1+} f(x) = e^2 - 1
>limit x to infinity of f(x)
lim_{x to infinity} f(x) = -1


Looking at the maximum at those you see that the supremum of the function is e^2 - 1 and a global maximum doesn't exist.
It could also have been useful to plot it which makes this obvious too.

[Anonymous No.14807544]

Why is it vacuously true that the relation R = empty set on the set S = empty set is reflexive?

I thought you could have vacuous truths for symmetric, antisymmetric, transitive bevause they all involve conditional statements where the antecedent is false so the statement is true by definition.

But reflexive is just "for all elements a in the set A, (a,a) is in the set R" right? All I can see is there's no elements in R or S

[Anonymous No.14807555]

>>14807544
If you can't see it directly try looking at the negation of this statement which is
>There exists an element a in the set S such that (a,a) is not in R.
which is trivially wrong as there is no element in S.

[Anonymous No.14807590]

>>14798375
> could "learning" be a step function % of neurons firing

No, your proposed model is plainly incomplete. There has to be a more sophisticated and structured mechanism to learning than merely the proportion of firing neurons.

An epileptic seizure can involve a large proportion of neurons firing but doesn't correspond to a great degree of learning.

[Anonymous No.14807599]

>>14807555
Ty for the suggestion I will try and think about it this way

[Anonymous No.14807604]

>>14799352
It would count as a proof if the algebraic properties that you are employing in it are at your disposal. And, in this case, you should clearly describe the rules that you are using.

Ordinarily, a proof proceeds from the field axioms. See, for example, Rudin's POMA p. 5.

The property you have used to get to your second equation, that -x = (-1) * x, is NOT a field axiom and you would need to also prove it. In a field, the element -x is not defined as (-1) * x but rather the additive inverse of x, that is, the element y that satisfies x + (-x) = 0.

[Anonymous No.14807785]

>>14806817
It will only turn on for half the cycle, so you'll get a 50/60 Hz flicker. You also have to take care a) to choose the resistor based upon peak voltage, not RMS, and b) not to exceed the reverse voltage (which is typically lower for LEDs than regular diodes).

Also: >>>/diy/ohm

[Anonymous No.14807908]

>>14796587
What is the cause of anxiety? What makes one person more anxious than another?

[Anonymous No.14808695]

>>14807908
worries

[Anonymous No.14808946]

What does it mean for a photon to have angular momentum? Is it circular polarization? If a star was spinning fast enough, would its light have circular polarization?

[Anonymous No.14809109]

>>14808946
photons have intrinsic spin, this contributes to them having a spin angular momentum which is related to their polarization
light can also have orbital angular momentum, which is a bit harder to grasp, and relies on the dynamics of the light field. I'm less familiar with discussing this topic as it's not very relevant in most physics

for your last question, polarization is an instantaneous property and doesn't depend on the dynamics of the source

[Anonymous No.14809428]

Suposedly agriculture was discovered approximately 10,000 years ago, yet the people who migrated to the Americas did so in multiple waves approximately 50k-15k years ago, yet the peoples of the Americas used agricultural. Was this a shared technology, or an independent discovery?

[Anonymous No.14809542]

>>14809428
> approximately 50k-15k years ago
not sure where you got that idea of 50k from. it was only recently that the earliest agreed upon date was around 12k years and its only in the last several years that has been pushed back earlier another 1-2k years. as for agriculture, in south america's the earlier evidence is around 9000 years old.

[Anonymous No.14809547]

Can anyone recommend a REAL Analysis problem book where the questions are not structured in a way that you can predict what theorems are you supposed to use by their placement in the sections? The question should be mixed and distributed somewhat randomly basically.

[Anonymous No.14809720]

Is this guy's advice on learning QFT as a mathematician any good? https://www.reddit.com/r/math/comments/fm8z39/comment/fl39xvl/?context=3

[Anonymous No.14809778]

>>14809720
From a mathematical perspective it looks fine but I think he, as a mathematician, largely underestimates the physics background require to know the *why* all that math exists and what it means. Either way all those texts are incredibly dense and technical, and not for the faint of heart.

[Anonymous No.14809784]

>>14809428
It was multiple independent discoveries. Agriculture developed separately in Mesoamerica, the Andes and the Amazon. Its been argued that agriculture further north developed inauthentic independently as well, but this is more controversial and it may have diffused from Mesoamerica.

[Anonymous No.14809858]

>>14809547
Answer real analysis questions in /sqt/ and stackexchange.
The questions are completely random, possibly have no answer, and are at least hard enough to have filtered the person asking.

[Anonymous No.14809951]

>>14809858
>stackexchange
Holy shit, why did I not think of this?

[Anonymous No.14809952]

[math]\!\mathfrak{Has\;this\;ever\;been\;solved?}[/math]

[Anonymous No.14809991]

>>14809952
If only there were /sci/ archives which let you like, search for all of the times an image was posted. If only.

[Anonymous No.14810557]

Has anyone here got the 3-volume A Shorter Course in Theoretical Physics by Landau-Lifshitz in full? I can only find volume 2.

[Anonymous No.14810901]

is agi actually possible?

[Anonymous No.14811125]

This exercise is completely wrong, right?
None of the limits turned out to be what's written here for me and most importantly I got [math] \Delta_n \to \frac{4}{5} [/math].

By the way
[eqn]S_{n,n} = \sum_{j=1}^n \sum_{k=1}^n a_{j,k} [/eqn]
[eqn] \Delta_n = \sum_{i = 0}^n \sum_{k = 0}^i a_{i-k,k} [/eqn]

[https://archive dot ph/uy5Hc No.14811130]

>>14796638
cute flan.

[Anonymous No.14811155]

>>14811125
>mentions positive integers m and n, no mention of m.
>a_(i-k, k) is undefined for k=0, so delta_n is not well-defined

[Anonymous No.14811775]

what is the driving force for fluids?
i thought it was pressure, but the Bernoulli equation (which is an energy equation) shows that a region of a pipe between a reducer and expander can have a lower pressure than both of its connection sides, but still flow from the overall higher pressure to lower pressure
is the driving force for fluids the energy difference?

[Anonymous No.14812064]

Is the principle of maximum entropy a meme? Wherever it's explained it says "according to MaxEnt you /should/ choose the maximum entropy distribution" without giving a quantitative argument why. Yes it maximizes entropy, but so what? Does that help us get to the right answer the fastest? "It is the most uncertain distribution." Every prior is umcertain if we know nothing, assuming Bernouilli trial is 100:0 is just as much of a shot in the dark as assuming it's 50:50. I am getting the impression nobody knows how information theory works (entropy, uncertainty, unorderliness, surprisal, and information content are all conflated with poor justification beyond misleading intuition) and I'm starting to believe MaxEnt is nothing but an aesthetic choice.

[Anonymous No.14812083]

>>14809778
Alright, thanks. I just wanted to make sure the prerequisites for QFT are really as he says they are and I'm not getting memed

[Anonymous No.14812152]

>>14796587
could someone walk me through how they got the answer using completing the square. Just show me how they got it for the x variable, i should be able to figure out the rest(yes im dumb)

[Anonymous No.14812156]

>>14812152

[Anonymous No.14812206]

>>14812156
yeah i get that but i dont know how to use completing the square to solve this

[Anonymous No.14812227]

>>14812206
(x-1)2 + (y-2)2 + (x+3)2 = 14

[Anonymous No.14812254]

>>14812206
You have 8. So you give yourself a fake 1 by adding 1 and subtracting 1. 8 = 8 + 1 -1.

Then you group them like (8 + 1) - 1 = [math]3^2[/math] - 1. Now you have the same shit but you write it different. In this case, you have polynomial and you want a nice square root in the form of (x + a)^2. So you add the missing shit, subtract it, too, so it's still 0, then rewrite the equation plus the missing shit in the form you want. Now you can pattern match it into other shit that's written in a form that most people are more used to. Nothing changed, you just changed the squiggles to look like other squiggles that look more like some other asshole's squiggles that everyone else also likes. Eventually you can get paid to do this if there are enough squiggles to do this with. How the fuck is this shit real?

[Anonymous No.14812328]

My tokens ran out on OpenAI GPT-3, and I was wondering if there is any free alternative. I've tried other ones, but none seem even remotely as powerful.

[Anonymous No.14812349]

How?

The RHS is equal to the power series
[eqn]\sum_{k=0}^\infty z^k [/eqn]

Isn't the LHS equal to some power series
[eqn]1 + \sum_{k=1}^\infty a_k z^k [/eqn]
where [math]a_k[/math] is equal to the number of ways [math]k[/math] can be written as a sum of distinct odd non-negative integers? Generally [math]a_k \neq 1 [/math].

Two power series can only be equal on an interval if all coefficients are the same.

[Anonymous No.14812429]

How do I transform cartesian basis vectors to polar, cylindrical or spherical coordinate basis vectors?

[Anonymous No.14812440]

Second week of class and I'm turning out to be very bad at digital logic and boolean algebra. Active-low logic hurts my fucking brain. Is it functionally different from a complement in a truth table?

Say for an active-low input into an active-low output, in a truth table if I had a 0 for the input it would be asserted, right? So it'd be showing a high signal to the output (which is also active-low) so whatever output I have would be functionally OFF since it's not a low?

Would that still be a 0 input 0 output for a truth table since the actual output value is a low?

[Anonymous No.14812451]

>>14812064
https://en.wikipedia.org/wiki/Bayesian_probability
>Maximum entropy
>(Unfortunately, it is not clear how to assess the relative "objectivity" of the priors proposed under these methods)
>"objective"
>"default"
>"regular"
>The quest for "the universal method for constructing priors" continues to attract statistical theorists.
We really haven't got a clue, do we?

[Anonymous No.14812537]

>>14812429
https://en.wikipedia.org/wiki/Cylindrical_coordinate_system#Cartesian_coordinates
https://en.wikipedia.org/wiki/Spherical_coordinate_system#Cartesian_coordinates

[Anonymous No.14812580]

genetically_enhanced_badger got me a /sci/ dump and now eientei.xyz has better post coverage than warosu.

Still way fewer images tho.

Also there are probably some posts that snuck in soliciting illegal material, but there are no images so HOPEFULLY it's fine.

[Anonymous No.14812590]

How do I make (-1)^n alternate every multiple of 3, instead of 2.

[Anonymous No.14812595]

>>14812590
Use [math]\left( -\frac{1}{2} + i \frac{\sqrt{3}}{2} \right)^n[/math].

[Anonymous No.14812596]

>>14812590
Wdym alternate every multiple of three?
[math]1, 1, -1, 1, 1, -1[/math] and so on and so forth?

[Anonymous No.14812602]

>>14812595
That squared does not give 1.

>>14812596
Yes.

[Anonymous No.14812624]

Hi anons, how do I make a relation that is both not symmetric AND not anti symmetric?

I'm getting stuck because anti is:
aRb ^ bRa -> a=b

And symmetric is:
aRb -> bRa

So if I try and make it not symmetric then it becomes vacuously true for antisymmetric because one of the antecedent(s?) becomes false, so it becomes automatically true like F ^ T -> F, so F -> F, which is T.

Also is x = -y not symmetric (because y = -x)? All the questions I've seen ask the relation x=y OR x=-y (which is symmetric), but never just x=-y on its own.

[Anonymous No.14812631]

>>14812602
If you want that sequence then you can take.

[eqn]\frac{1}{3} - \frac{2}{3} \left( \left( -\frac{1}{2} + i \frac{\sqrt{3}}{2} \right)^n + \left( -\frac{1}{2} - i \frac{\sqrt{3}}{2} \right)^n \right) [/eqn]
or the same formula written differently as
[eqn] \frac{1}{3} - \frac{4}{3} \cos \left( \frac{2 \pi n}{3} \right) [/eqn]

[Anonymous No.14812637]

>>14812631
I am wondering if there is a polynomial sequence [math] p(n)[/math] such that [math] (-1)^{p(n)} = 1, 1,-1,\dots[/math]

[Anonymous No.14812662]

>>14812624
that'd be an asymmetric one, no? aRb -> ~bRa
< would be an example of one since 1<1 is false and 1<2 implies ~(2<1)

[Anonymous No.14812666]

Mathematicians and /sci/entists: how do I 'model' stuff? I only know how to use Excel and Powerpoint.

[Anonymous No.14812668]

>>14812666
>stuff
What is stuff?

[Anonymous No.14812677]

Anyone know what the English name for the property „Drittengleicheit“ ([math]a R c \land b R c \Rightarrow a R b[/math]) is?

[Anonymous No.14812688]

>>14812677
Dunno, but transitivity is almost what you are asking.

[Anonymous No.14812689]

>>14812677
Transitivity.

[Anonymous No.14812693]

>>14812688
>>14812689
That condition is equivalent to symmetry + transitivity according to the book I read. Not sure if it has an English name.

[Anonymous No.14812812]

I’m African and family is from but I’m not “black.” I want to apply for African American scholarships and they require you to be African and/or black. Can I apply to these scholarships?

[Anonymous No.14812821]

>>14812812
Why the fuck are you asking /sci/? Ask them, but you probably shouldn't, they'll realise the loophole and patch it quick to only be applicable to blacks. Just apply without saying anything about your race.

[Anonymous No.14812835]

>>14812812
>I’m African
>they require you to be African
I'm not seeing a problem here.

[Anonymous No.14812856]

>>14812662
Ty anon

Is x=-y symmetric?

Its not reflexive because x != -x.
It's not transitive because 1R-1 and -1R1 but 1!R-1

Does that mean it can't be symmetric?

[Anonymous No.14812857]

>>14812856
Sorry I meant but 1!R1 not 1!R-1

[Anonymous No.14812867]

>>14812637
What is the ... implying for the continued pattern?

[Anonymous No.14812872]

>>14812867
Repeat the whole thing.

[Anonymous No.14812946]

>>14812856
I think it would be trichotomous ([math]\forall x,y: (xRy \lor x=y \lor yRx)\land \sim((xRy\land x=y)\lor (yRx \land xRy) \lor (yRx \land x=y) )[/math]), as either xRy (x=-y), x=y (0=0), or yRx (y=-x) holds (and not any two or more of them at the same time), and that is equivalent to it being asymmetric and connected ([math]\forall a,b: aRb \lor a=b \lor bRa[/math]). It doesn't need to be transitive. In this case, it would be, I believe, intransitive (so: [math]\exists a,b,c: aRb \land bRc \land \sim (aRc)[/math], [math]\exists[/math] instead of [math]\forall[/math], since it's true for [math]a=b=c=0[/math], and, more generally, [math]\sim \forall x P(x) = \exists x \sim P(x)[/math]).
Someone, please correct me if I'm wrong.

[Anonymous No.14812994]

When logicians use the symbol [math]\ni[/math] for “such as”, is that arbitrary or actually the inverse of [math]\in[/math]?

[Anonymous No.14813063]

>>14812994
nolispe

[Anonymous No.14813068]

>>14812994
to be more specific, I mean the "logical inverse of [math]\in[/math]"

[Anonymous No.14813137]

>>14813068
[math]x\in S \iff S \ni x[/math]
Pretty rare, I've only seen it in function definitions like [math]X \ni x \mapsto f(x)\in Y[/math]

[Anonymous No.14813187]

>>14812872
you mean like this?
[math]1,1,-1,1,1,-1,1,1,-1,\cdots[/math]
If that's the case then simply define
[eqn]p(n)=\begin{cases}1&n\text{ is divisible by 3}\\0&\text{else}
\end{cases}[/eqn]
Alternatively
[math]\text{sgn}(n\mod3)[/math]
where sgn is the sign function

[Anonymous No.14813195]

>>14813137
I use it when I want to write x∈X but I forget the "x∈" part and just write "X" and im too lazy to erase it so i just do "X∋x"

[Anonymous No.14813200]

>>14813137
If it's really "such that" I will use it in my proofs from now on

[Anonymous No.14813203]

>>14812872
>>14812637
you mean like this?
[math]1,1,-1,1,1,-1,1,1,-1,\cdots[/math]
If that's the case then simply define
[eqn]p(n)=\begin{cases}1&n\text{ is divisible by 3}\\0&\text{else}\end{cases}[/eqn]
Alternatively
[math]\text{sgn}(n\mod3)[/math]
where sgn is the sign function

[Anonymous No.14813215]

>>14813203
you know what, fuck you 4chan i'm tired of fixing latex shit

[Anonymous No.14813224]

>>14813215
gitgud

[Anonymous No.14813315]

>>14813224
apparently having two math tags fucks up the LaTeX because the interperter closes the first tag with the second one, i.e.
[m4th]some math shit[/m4th] some other shit [m4th]even more math shit[/m4th]
will be rendered as
[math]some math shit[/math] some other shit [math]even more math shit[/math]

[Anonymous No.14813325]

>>14813315
huh that worked nvm, ignore this post
4chan LaTeX still sucks

[Anonymous No.14813369]

>>14776414
>suspended multiplication
What does this mean?

[Anonymous No.14814238]

Why do Lanthinides and Actinides exist only on the 6th and 7th rungs of Mendelev's Periodic Table?
It's so anomalous that it wouldn't be beyond God's imagination for Element 119 to exist.

[Anonymous No.14814257]

>>14796587
Just wanted to thank you all for all your help anytime I needed it.

I'm going to get my affairs in order in the next two weeks then off myself. Thank you again anons

[Anonymous No.14814276]

>>14814257
Don't do it bro.

[Anonymous No.14814289]

>>14814276
I have to. I realized I'm a defective human. I can't embrace the suck like Sisyphus anymore.

[Anonymous No.14814513]

You're telling me humans landed on the moon with the processing power of a #2 pencil? That's honestly unbelievable. Just look at this.

[Anonymous No.14814842]

>>14796587
Just ordered this for father's day... how fucked am I when the Genesplicer pirates break Church's blockchain and steal my father's genes to clone him?

[Anonymous No.14814859]

>>14814257
Do it bro. Don't listen to demoralisation fags like >>14814276
It never gets better for us.

[Anonymous No.14814889]

>>14814842
You know that ₪ is the Hebrew symbol for Shekels, right?

[Anonymous No.14814894]

Are these boundary conditions homogenous? And, if so, can I use the Newman Method to split [math]\phi(x,y,t)[/math] into [math]\phi(x,t)*\phi(y,t)[/math] ?

[eqn]
\left\{\begin{array}{@{}4@{}}
\phi(x,y,0)=1\\
\phi(0,y,t)=1\\
\frac{\partial \phi(x,0,t)}{\partial y}=0\\
\frac{\partial \phi(L_x,y,t)}{\partial x}=\frac{-h}{k}\phi(L_x,y,t)\\
\frac{\partial \phi(x,L_y,t)}{\partial y}=\frac{-h}{k}\phi(x,L_y,t)
\end{array}\right.\,.
[/eqn]

[Anonymous No.14814900]

Brainlet here, if a video runs at 60 FPS then how many seconds would 10 frames be?

[Anonymous No.14814902]

>>14814900
1/6th of a second

[Anonymous No.14814903]

>>14814900
60 frames =1 second
10 frames = x

x=10/60=0.167s

[Anonymous No.14814904]

>>14814900
Muhammad, is that you?
How's FIFA mobile going?
It's been so long since we last met, when we were in school.

[Anonymous No.14814906]

>>14814889
We're pretty proud Jews. And the Genographic Project was started for Moishes like me.

[Anonymous No.14814908]

>>14814902
>>14814903
Thanks, my brain feels less small now.

>>14814904
I don't know who you're talking about.

[Anonymous No.14814911]

>>14814906
>proud
Chutzpah or hubris?

[Anonymous No.14814977]

>>14814911
Lord Jonathan Sacks, perhaps put it best when he said, "Non-Jews respect Jews who respect their Judaism. Non-Jews are ashamed by Jews who are ashamed by their Judaism."

[Anonymous No.14814980]

>>14814977
Can you trace your lineage to the 12 Patriarchs and to Abraham?
I think not!
>שו מנצרת, מלך היהודים

[Anonymous No.14814987]

>>14796587
Why arent n degree polynomials called n-polynomials. Just like manifolds, you dont say n dimensional manifold but n-manifold.

[Anonymous No.14815001]

>>14814980
Lol.

[Anonymous No.14815010]

>>14813195
Based utilitarian proover

[Anonymous No.14815112]

I know this is extremely basic shit but I feel like khan academy is just fucking with me here
this is an arithmetic sequence of multiplying the number by 3, right?

[Anonymous No.14815115]

Did I rationalize the denominator correctly bros?

[math] \frac{x}{\sqrt[3]{x+2}}*\frac{(x+2)^{2/3}}{(x+2)^{2/3}} \\\\\\ \frac{x(x+2)^{2/3}}{x+2} [/math]

[Anonymous No.14815117]

>>14815115
the denominator should be x+2 not x+5

[Anonymous No.14815120]

>>14815112
It looks like a geometric sequence. Not that anyone can say for certain because it doesn't give a formula for the "...".

[Anonymous No.14815125]

>>14815112
>this is an arithmetic sequence of multiplying the number by 3, right?
yea, its [math]3^n[/math]

[Anonymous No.14815130]

>>14815120
>>14815125
I'm just baffled because in the top one, they say it is an arithmetic sequence with multiplying by 2, but then it suddenly isn't when you can multiply by 3 because they choose to present it as just adding

[Anonymous No.14815135]

>>14815130
>in the top one, they say it is an arithmetic sequence with multiplying by 2
where?

[Anonymous No.14815138]

>>14815135
here it's a sequence, 3, 6, 12, 24, multiplying by 2
but on the bottom, you can achieve the same sequence by multiplying each number by 3
3, 9, 27, 81, 243, etc.
but they say that ISN'T an arithmetic equation

[Anonymous No.14815139]

>>14815130
Arithmetic sequence means [math]a_{n+1} - a_n [/math] is constant for all [math] n[/math].
Geometric sequence means [math] \frac{a_{n+1}}{a_n} [/math] is constant for all [math] n[/math].

The only sequence that is simultaneously a arthmetic sequences and a geometric sequence is the sequence
[math]b_n = 1[/math] for all [math] n[/math] .

[Anonymous No.14815142]

>>14815139
so if the number *2 is an arithmetic sequence, then why isn't the number *3 one?
not trying to be combative, I just don't get how one is different from the other

[Anonymous No.14815144]

>>14812994
I've never seen that usage by a mathematician. By logician do you mean a philosophy teacher?

[Anonymous No.14815147]

>>14815142
>the number *2 is an arithmetic sequence
please point to the exact location of that claim

[Anonymous No.14815156]

>>14815147
these are from two problems on the same sheet about arithmetic sequences
in the bottom one they give the explanation as
3+6 = 9, 9+18=27, 27+54=81
when it could just as well be
3*3 = 9, 9*3=27, 27*3=81
making *3 constant, no?

[Anonymous No.14815164]

>>14815156
read >>14815139 again. the sheet is clearly showing that the arithmetic difference (simple subtraction) of consecutive terms is not constant. the *3 is a constant, which does make it a geometric sequence, but it would have to be +3 (or some other number) for it to be arithmetic.

[Anonymous No.14815169]

>>14815164
I haven't gotten to geometric sequences yet so I guess that explains why I don't get it
it just seems like they're effectively the same to me so it confuses me but hopefully I'll understand it better

thanks for explaining lads

[Anonymous No.14815176]

>>14815169
this isnt hard. do you see how
2, 4, 6, 8, 10, 12, ...
has terms where the difference is constant, 2, but
5, 25, 125, 625, 3125, ... (powers of 5)
has terms where the difference is getting bigger and bigger? this make the first one arithmetic, and the second one not arithmetic.

[Anonymous No.14815180]

>>14815176
>this isnt hard
I'm a 24 year old man struggling with high school algebra, it is unfortunately pretty hard for me
so does it basically boil down to add/subtract = arithmetic and multiply/divide = geometric?

[Anonymous No.14815182]

>>14815180
>add/subtract = arithmetic and multiply/divide = geometric?
yeah

[Anonymous No.14815183]

>>14815180
>does it basically boil down to add/subtract = arithmetic and multiply/divide = geometric?
yes, thats right.
hang in there, anon, we're here for you.

[Anonymous No.14815189]

>>14815182
>>14815183
thanks again, frens
I appreciate the help

[Anonymous No.14815195]

>>14815139
>The only sequence that is simultaneously a arthmetic sequences and a geometric sequence is the sequence [math]b_n=1[/math] for all [math]n[/math] .
any number would work, it doesnt have to be 1.

[Anonymous No.14815222]

Let [math] O_1 = (a_1,b_1)[/math] and [math] \forall i \in \Bbb N - \{1\} \left( O_i = (a_i, b_i) \right)[/math] where [math] a_i = \frac{1}{3} (a_{i-1}+b_{i-1})[/math] and [math] b_i = \frac{2}{3} (a_{i-1} + b_{i-1})[/math].

[math] \textbf{Is the set } \bigcap_{i\in \Bbb N} O_i = \frac{1}{2} (a_1 + b_1) \textbf{?}[/math]

[Anonymous No.14815225]

Why does modulo have the transitivity property?

[Anonymous No.14815251]

>>14815144
I'll see if I can find the textbook I saw it in. I've also found pic rel online

[Anonymous No.14815274]

>>14812994
>>14815251
It's obviously not the logical inverse. I don't even understand why would you ever need an explicit such that symbol. It is already implied between punctuations.

[Anonymous No.14815360]

>>14815251
Midwits tend to make lists like this. It's like carrying around a list of the 20 most used english words just in case you forget what one of them means.

[Anonymous No.14815569]

>>14815222
Let [math]a_1 = 1/3[/math] and [math]b_1 = 2/3[/math]
Then all [math]O_i = O_1[/math\], so no.

[Anonymous No.14815954]

>>14815225
> modulo transitive property
If by that you mean if [math]x\equiv y \pmod m[/math] and [math]y \equiv z\pmod m[/math] then [math]x\equiv z\pmod m[/math] it is because:

1) [math]x\equiv y \pmod m[/math] means that [math]m\ |\ (x - y)[/math]
2) [math]y\equiv z \pmod m[/math] means that [math]m\ |\ (y - z)[/math]

So that must also be true for their sum, such that [math]m\ |\ (x - y) + (y - z) \implies m\ |\ (x - z)[/math] so [math]x\equiv z\pmod m[/math]

[Anonymous No.14816410]

Does risperidone have any long-term permanent effects?

[Anonymous No.14816422]

>>14816410
Gyno tits.
It's an oestrogen mimicker.

[Anonymous No.14816476]

What are the best lighting conditions to take a photo of a coloured, transparent medium that I might register the colour pixel in hexadecimal and replicate the colour in another medium?

[Anonymous No.14816789]

if the FFT is used to find the fourier transform of some function in [math]O(Nlog(N)[/math], and the FFT is practically an involution/its own inverse, does that mean there exists an inverse FFT that can really quickly generate a waveform from an array of fourier coefficients?

[Anonymous No.14816858]

>>14816789
Yes. The inverse FFT is also O(n.log(n)). This is a popular technique for generating "rough" water surfaces, as you can sum thousands of individual sine waves fast enough for real-time animation.

[Anonymous No.14817180]

I got one assignment left to do in Scratch, need some help. Because I have no idea how to do it.

> One day there was a lot of noise in a class. The teacher (who was an extremely logical person) got annoyed and said:
> "If you don't shut up now, you'll get a maths test!"
> 1. Suggest how the teacher can program what he is thinking of doing. Use a selection chart.

> 2. The students were quiet, and the teacher still gave them a maths test! Was the claim above a lie? In other words, it is possible to create a choice diagram (as in the previous question) that both corresponds to what the teacher said (Claim), and what did he do (that the students were given a maths test)?

> 3. Write a truth table for "If A, then B".

[Anonymous No.14817374]

Can someone recommend a /fa/ scientific calculator. Either a sleek modern design or something incredibly compact, like buttons so small you have to press them with your pencil. I can find anything that satisfies my autism

[Anonymous No.14817393]

>>14817374
No.

[Anonymous No.14817395]

>>14817180
>> 3. Write a truth table for "If A, then B".
One column for [math]A[/math], one for [math]B[/math], and one for [math]A\Rightarrow B[/math]. Then fill in either true or false in [math]A[/math] and [math]B[/math]'s columns respectively such that they only are either both true or both false in a row once, then think about whether [math]A\Rightarrow B[/math] holds for each entry. So, if both [math]A[/math] and [math]B[/math] are false, for instance: "If [math]A[/math] is false and [math]B[/math] is false, does '[math]A[/math], then [math]B'[/math] hold?", etc.

[Anonymous No.14817424]

>>14817393
You didn't even look, anon

[Anonymous No.14817535]

>>14815115
>>14815117
bros, ples help. I even wrote it in lah tech for you.

[Anonymous No.14817638]

>>14817535
[eqn]\frac{x^2}{(x+2)^{1/3}}*\frac{(x+2)^{2/3}}{(x+2)^{2/3}}=\frac{x^2(x+2)^{2/3}}{x+2}[/eqn]

[Anonymous No.14817697]

>>14817638
spasiba, fren.

[Anonymous No.14817776]

Is it true for all topo spaces that if x is an e neighbour of y, then y is an e neighbour of x.?

[Anonymous No.14817798]

>>14817697
cпacибo дпyг

[Anonymous No.14817878]

what is a limit?

[Anonymous No.14817891]

>>14817878
There's no such thing brah

[Anonymous No.14817920]

>>14817798
cпacyбo, дpyг
Got confused with the stupid Deathclaw meme sorry.

[Anonymous No.14818341]

I am a fresh Electrical engineering graduate and got a job as a controls engineer at an aerospace company that makes turbofan engines.
Any recommendations for good textbooks or maybe online courses and lectures that will make me more knowledgeable on aerospace engineering in general and military aircraft more specifically

[Anonymous No.14818416]

I'm confused. If you say [math]p\neq 1[/math], then wouldn't you have to say [math]n\neq 1[/math] in this case too? As in every natural number BUT 1 can be represented as a product of prime numbers (as [math]1\in\mathbb{N}[/math] too but [math]p\neq 1[/math], hence it can't be represented as a product [math]p_1 \cdots p_k[/math]).

[Anonymous No.14818426]

is there a name for an object that is both a monoid under addition and multiplication? Or do you just say it's isomorphic to the natural numbers?

[Anonymous No.14818457]

>Analogously, the Minkowski difference (or geometric difference)[1] is defined using the complement operation as
[math]A-B=\left(A^{c}+(-B)\right)^{c}[/math]
What does (-B) mean here? negative set??

[Anonymous No.14818469]

>>14818416
Note that they didn't wrote that [math]k \geq 1 [/math]. For [math]k = 0 [/math] you get the empty product which is equal to 1.

[Anonymous No.14818474]

>>14818457
You multiply every element in B with -1.
[eqn] -B = \{-b | b \in B \} [/eqn]

[Anonymous No.14818535]

>>14818469
Thank you, this makes a lot of sense. I take it the index set is usually assumed to be [math]\{ 0, 1, ..., n\}[/math]?

[Anonymous No.14818747]

For people who jumped from physical sciences (mainly talking about chemistry) to data science or data analysis , what experience/skills were useful for that jump?

[Anonymous No.14818935]

I'm trying to prove that
[eqn]\int_{0}^{\infty} \frac{x^{\alpha-1}}{1-x}dx = \pi \cot(\alpha\pi)[/eqn]
without using contour integration, which I already done. I want to do it using Beta and Gamma functions and their identities.
any one has a suggestion on this? some change of variable to try? I already tried [math]t=\frac{x}{1-x}[/math], [math]t=\frac{1}{x}[/math], and some others with no success.

[Anonymous No.14819212]

>>14796587
could someone help me work out this one? im almost out of tries

[Anonymous No.14819453]

Am I retarded if I can't figure this out?

[Anonymous No.14819474]

>>14819453
Do you even know what induction is? Prove the base case (n=0) then prove for n+1

[Anonymous No.14819477]

>>14819474
Yeah, I can't figure out the n+1 part

[Anonymous No.14819487]

>>14819477
Do you remember how [math]\displaystyle \sum_{i = 0}^{n + 1}[/math] is defined?
Quite literally we have that [math]\displaystyle \sum_{i = 0}^{n + 1} a_i = \displaystyle \sum_{i = 0}^n a_i + a_{n + 1}[/math]

[Anonymous No.14819498]

>>14819474
assume that P(n) = n + 1 is true, then P(n + 1) = (n + 1) + 1 = P(n) + 1

[Anonymous No.14819513]

>>14819487
>>14819498
This is what I have so far

[Anonymous No.14819516]

>>14819513
Then what else were you expecting? The question is meant to be trivial.

[Anonymous No.14819518]

>>14819513

[Anonymous No.14819529]

>>14819518
where did that k magically appear from??

[Anonymous No.14819535]

>>14819487
>>14819516
No, I guess I don't quite follow.

[Anonymous No.14819538]

>>14819529
Step 2 of mathematical induction
Once you've assumed it holds true for n, assume it holds true for k + 1, with k = n.

[Anonymous No.14819550]

>>14819538
We all know that, no one is that stupid here. However you don't seem to understand how to apply that rule to the expression inside the sigma. You just add 1, not k+1

[Anonymous No.14819567]

>>14819550

[Anonymous No.14819573]

>>14819567
I didn't do this correctly did I?

[Anonymous No.14819600]

>>14819567
Okay now I see how I fucked up. I guess I'm really rusty on how the summations work. I haven't done stuff with math in a while and this class is terrifying me so far, also... just kinda reconsidering my entire life right now.

>>14819538
Also this wasn't me, which is really weird.

[Anonymous No.14819623]

i need help with this last one.

Not sure what im doing incorrectly

i thought the equation is

m/l = IBsin / (g)

then convert from kg to g since it wants in g/m

[Anonymous No.14819669]

>>14819600
>I haven't done stuff with math in a while and this class is terrifying me so far, also... just kinda reconsidering my entire life right now.

[Anonymous No.14819832]

>>14796587
Can I take the limit of a function that explicitly takes integer argument? Or does it only work for real-valued functions?

[Anonymous No.14819859]

>>14819832
You can take the limit at ±∞; a function which takes an integer argument is essentially a sequence.

[Anonymous No.14820239]

I am getting filtered trying to prove that a set cannot have uncountable number of isolated points. My current strategy is to consider the set of all isolated points for a set, and hope to show that it is countable. Will this work? If you feed me the complete proof straightaway, your mother will die in her sleep tonight.

>>14819832
If it is a convergent sequence with nonnegative input (or with a lower bound on its input), yes you could consider the limit at infinity. If the input is not bounded below, you could separate the the sequence at 0, and consider negative and positive inputs separately, which would give you the negative and positive limits. But then it needs to be convergent on negative side as well, if you want to find the limit at negative infinity.

[Anonymous No.14820276]

I was reading some astrophysics for fun and I must ask: do astrophysicists have any clue what entropy and temperature mean? Are they aware that entropy is related to the number of microstates for a specific macrostate, that one must assume there is a very large number of particles, and that energy states are constantly shuffling around to turn this into a statistical (but in the thermodynamic limit very sharply peaked) process? How is "the heat death" of the universe a thing, when due to Hubble expansion, matter gets more and more separated until it becomes so rarified that the laws of thermodynamics simply aren't applicable any longer. Except for black holes, which accumulate matter; but according to Berkenstein and Hawking they evaporate—a process which in itself is theorized on the assumption that when an entropic object goes into a black hole its entropy vanishes and to preserve the Second Law that entropy must be encoded into the black hole's surface... somehow. I don't believe any of it, and for the record, I am a PhD student in theoretical physics.

Anyway, I want to boil this down to one question about black hole evaporation: the evaporation rate is said to occur in accordance with the Stefan–Boltzmann law, where the temperature is the black hole temperature. If I am not mistaken, evaporation is complete when all mass has been converted into Hawking radiation; since there is nothing left at that point, the entropy of the black hole has become zero. But if the universe strives towards thermodynamic equilibrium, how can that happen? It seems to me black holes don't evaporate completely (assuming this theory is valid of course), but they evaporate to the point that the black hole is in thermodynamic equilibrium with the rest of the universe. I want to know this because the view that all black holes will evaporate seems to be a commonly held one, to the point that it seems to gets treated as a scientific fact.

[Anonymous No.14820344]

If I add the first and third term together and then add it to the second, is this making using of both associativity and commutativity?

[Anonymous No.14820356]

>>14820344
Yes.
>(a + b) + c (Premise)
>c + (a + b) (Commutativity)
>(c + a) + b (Associativity)
Now evaluate the brackets.

[Anonymous No.14820382]

>>14820276
> how can that happen?
the "temperature" of a black hole is not real. in actuality the important property is its entropy, which in classical thermodynamics you can then equate to a temperature, that is what they are talking about, however the black hole is not physically hot or cold - it's just a way to talk about the black hole in simple terms.

thermodynamics says that entropy always increases in a closed system, but in this case the closed system is the entire universe and with hawking radiation that still holds true.

[Anonymous No.14820398]

>>14820382
I am fully aware that temperature is not just a measure of hotness but the change of energy per unit of entropy. It comes down to the same thing, thermodynamically: it's a property of a system that indicates the exchange of energy with another system in accordance with the Second Law: totaly entropy always increases. This is exactly the reasno that black hole temperature was invented: to resolve the paradox of entropy disappearing as an object falls into a black hole. By design it obeys the same properties as classical thermodynamic objects, namely that it strives towards equilibrium. But the theory of black hole evaporation states that evaporation happens until the black hole is gone, in other words until it reaches zero mass, zero entropy, and zero temperature. But this is simply impossible in thermodynamics.

[Anonymous No.14820401]

>>14820356
Thanks.

[Anonymous No.14820407]

>>14820398
> zero entropy, and zero temperature
artefacts of trying to apply a classical theory to an absurd limit. in reality the black hole will shrink to a small enough size where it will no longer be a black hole and so will never reach a point where its surface area is zero

[Anonymous No.14820414]

>>14820407
>artefacts of trying to apply a classical theory to an absurd limit.
This is how the lifetime of a black hole is calculated: integrate the mass from M(t=0) to 0(t=T) and see what evaporation time T rolls out.
>in reality the black hole will shrink to a small enough size where it will no longer be a black hole
I guess that's another possibility. But by what physical mechanism will it "stop" being a black hole? What order of magnitude are we talking about?

[Anonymous No.14820422]

>>14820414
> This is how the lifetime of a black hole is calculated
I'll say it again: applying some classical maths to a quantum system (or reality in general) doesn't mean that is what happens at the extreme limits. It's why infinities arise is lots of theories when misapplied. For example General Relativity says there's a singularity with infinite mass and zero size inside the black hole, but no physicist actually believes that happens. We know quantum mechanics will come into play to prevent that.

> What order of magnitude are we talking about?
That's still up for discussion since we don't have a quantum theory of gravity yet. General consensus is anywhere between atomic size down to planck scale. Either way you get to a point where the remnants of the black hole all just instantly turns into energy.

[Anonymous No.14820423]

>>14820414
> This is how the lifetime of a black hole is calculated
I'll say it again: applying some classical maths to a quantum system (or reality in general) doesn't mean that is what happens at the extreme limits. It's why infinities arise in lots of theories when misapplied. For example General Relativity says there's a singularity with infinite density and zero size inside the black hole, but no physicist actually believes that happens. We know quantum mechanics will come into play to prevent that.

> What order of magnitude are we talking about?
That's still up for discussion since we don't have a quantum theory of gravity yet. General consensus is anywhere between atomic size down to planck scale. Either way you get to a point where the remnants of the black hole all just instantly turns into energy.

[Anonymous No.14820445]

>>14820423
>I'll say it again: applying some classical maths to a quantum system (or reality in general) doesn't mean that is what happens at the extreme limits. It's why infinities arise is lots of theories when misapplied.
Then that is a criticism of astrophysics, not of mine, because the formula for black hole evaporation is a textbook fact. And I fully agree with you: the fact that we are talking about the evaporation of black holes when we haven't even figured out quantum gravity is extremely bold, especially considering the thermodynamic groundword is so poorly laid. Hence my skepticism.

>General consensus is anywhere between atomic size down to planck scale.
Interesting. I suppose it doesn't make too much of a difference, since the integral that calculates evaporation time very neatly converges, anyway. That last Planck length probably doesn't make too much of a difference. Still, if black holes obey thermodynamics as Berkenstein theorized, and if they thus tend to equilibrium, then the temperature of the environment must be lower than the temperature associated to that black hole size. For the temperature to lower further below equilibrium means violating the Second Law.

[Anonymous No.14820453]

>>14820445
> then the temperature of the environment must be lower than the temperature associated to that black hole
you're doing it again. they don't have a physical temperature they have entropy, that is more fundamental. you can't use that abstract temperature to talk about thermodynamics of the black hole interacting with the environment, it just doesn't work.

[Anonymous No.14820459]

>>14820453
You are wrong. The reason the concept of "black hole entropy" was invented is precisely because Berkenstein foresaw a violation of the Second Law and sought to remedy this by encoding entropy into the black hole's surface.
>that is more fundamental
This doesn't mean anything.
>you can't use that abstract temperature to talk about thermodynamics of the black hole
Again, that's literally the problem black hole thermodynamics is supposed to solve.

[Anonymous No.14820472]

>>14820459
You can use that temperature to talk about the black hole itself but you can't use it to talk about it and it's environment. How the concept of a black hole having entropy came about is almost irrelevant, current thinking these days is that it's entropy and hence configuration states are related to the allowed amount of quantum information a black hole can store and hence regarded as the more important, fundamental concept.

[Anonymous No.14820486]

>>14820472
>You can use that temperature to talk about the black hole itself
Then it is completely useless. Everything in physics, and especially in thermodynamics, is about how things interact. What's more, entropy scales with the area so it doesn't even bring anything new to the table.
>configuration states are related to the allowed amount of quantum information a black hole can store
Can it? The no-hair theorem says a black hole has no physical properties outside of position, (angular) momentum, mass and charge. This is why entropy is related to surface area: so it isn't something new. So we have a physical quantity which does not describe any interactions, only the thing in itself, and is directly given by measuring a different, more physical and variable quantity. To me that sounds like a completely redundant, indeed unphysical, concept.

[Anonymous No.14820502]

>>14820486
> Then it is completely useless.
Nope. It's useful as a simple, single term to use when writing equations you can then apply to the black hole. The same is actually true with classical thermodynamics. Temperature is not fundamental, it's an emergent property that arises from the interaction of the atomic particles in the system.

> To me that sounds like a completely redundant, indeed unphysical, concept.
Black holes sit right on the edge of between classical and quantum systems and are the cutting edge of theoretical research so if you don't understand everything then that is to be expected.

[Anonymous No.14820606]

>>14812349
It's false.

[Anonymous No.14820625]

>>14820502
>It's useful as a simple, single term to use when writing equations you can then apply to the black hole.
What does "apply to the black hole" mean?
>The same is actually true with classical thermodynamics. Temperature is not fundamental, it's an emergent property that arises from the interaction of the atomic particles in the system.
Yes, but this doesn't follow. I know temperature is an emergent property, but that fact is not relevant. What's important is that entropy tends to increase, and temperature can be considered a measure for how far out of equilibrium two systems are, and hence how much works can be extracted from them. Black hole entropy does not have this property so the only thing you can do with it is bookkeeping.
>Black holes sit right on the edge of between classical and quantum systems and are the cutting edge of theoretical research so if you don't understand everything then that is to be expected.
I expect you don't understand it, either. Glad to see my skepticism isn't entirely ill-founded.

[Anonymous No.14820630]

How did he get (3(pi))/4 ?
Shouldn't the answer be -1(pi)/4

[Anonymous No.14820631]

Can machines have souls?

[Anonymous No.14820632]

>>14820630
forgot pic

[Anonymous No.14820642]

>>14820631
Can't be answered since we have no scientific definition of the soul or if it is even real (it's not)

[Anonymous No.14820643]

>>14820631
"Souls" are not real.

[Anonymous No.14820646]

>>14820625
>I expect you don't understand it, either.
Well, yeah, no one does. That's the point and why so many theoreticians work on the problem.

[Anonymous No.14820662]

>>14820646
I suppose that answers my original question, thank you.

[Anonymous No.14820697]

>>14796587
In pic related, I have drawn the cross section of a coaxial cable. Since current flows through the inner cable and collects on the surface of conductors, that surface would be negatively charged.

Then the outside husk would be positively charged, since positive charges attract and negative charges are repelled. Then would the potential difference U be as in pic related? Or is that not how it looks in coaxial cables?

[Anonymous No.14820701]

>>14820697
Also, the voltage inside the cable is 0, since intuitively, the electric fields of the negative charges all cancel eachother out as they collect on the surface.

Just want to make sure that I've understood this correctly.

[Anonymous No.14821115]

If I mix Ice Tea with water, is that essentially the same as drinking water? Or do I also need to drink water by itself for it's effects? (I hate water)

[Anonymous No.14821133]

>>14821115
Serious question. Are you retarded?

[Anonymous No.14821161]

>>14818935
Can't help you here: the integral is straightforwardly divergent at x=1 for all alpha. Do you mean some sort of principal value?

[Anonymous No.14821181]

>>14821115
Drinking hypertonic solutions does the opposite of hydrating your body (that's why drinking salty sea water when you're thirsty is a bad idea), you need hypotonic or at least near isotonic solution
I don't know how much solutes are dissolved in ice tea but if i have to guess then it would probably be hypertonic so just drink regular water instead or if you really insist then make sure to dilute the tea with as much water as possible
>I hate water
How can you even hate water??

[Anonymous No.14821182]

>>14821115
No anon, it isn't. Are you trying to lose weight? Drink more water then fren, but occasional ice tea won't hurt (don't be a slob and drink litres of sugary ice tea though).

[Anonymous No.14821192]

Test
>>14821200

[Anonymous No.14821200]

>>14821192
yeah that's me, check my dubs!

[Anonymous No.14821225]

>>14821161
yup. precisely it about its principal value.
I did the integration of
[eqn]\oint_C \frac{z^{\alpha-1}}{1-z}dz[/eqn]
with [math]C[/math] being a closed contour, upper half semicircle indented at [math]z=0[/math] and [math]z=1[/math] and got the result with another well known result too, namely, [math]\int_0^{\infty} \frac{x^{\alpha-1}}{1+x} dx = \frac{\pi}{\sin(\alpha\pi)} [/math] . But I'm wanting to get this same first result using Beta and Gamma functions.

[Anonymous No.14821230]

>>14821200
Checked.

[Anonymous No.14821236]

Test 2
[math]2 + 2 = 4

[Anonymous No.14821334]

If I drank a litre of milk in one sitting without anything else to go with it, and had a bit of gas afterwards, does that mean I'm completely lactose intolerant, or could it just be that my digestive system is not used to that? I seem to be able to have as much butter and ice cream as I want perfectly fine (which is a lot).
I got a cool CAPTCHA: G2GPRP

[Anonymous No.14821387]

>>14821334
On a related note, how can I increase lactase production, assuming I'm not genetically lactose intolerant? I wouldn't have any problems from drinking a litre of milk throughout the day, but I'd like to be able to drink it all at once.

[Anonymous No.14821512]

Can someone give me a hint on how to start this one?

[Anonymous No.14821531]

>>14821512
Think of how you could use change of base to make this problem simpler.

[Anonymous No.14821545]

>>14821512
Change the base of ln(n) to log10

[Anonymous No.14821585]

>>14821512
lg(n) = log10(n) / log10(2)
multiply all sides by log10(2) then find A and B

[Anonymous No.14821614]

>>14821334
>>14821387
Update: I took a shit and it smelled nasty af and it was partially slightly liquidy. Never had that happen from something I ingested before in my life. Call me retarded but I think I'm gonna do this again tomorrow to see if I build up more tolerance, because I *think* I am genetically lactose tolerant (I look very Aryan) but my lactase production is just low compared to people doing GOMAD.

[Anonymous No.14821635]

>>14821614
If you can drink a liter of milk without abdominal pain or diarrhia then you're probably not lactose intolerant

[Anonymous No.14821657]

>>14821635
How severe of abdominal pain are we talking here? I had very, very slight pain from gas passing through my intestines, but it was nothing much. And by diarrhea, do you mean shit that's completely liquid, or just any less solid than normal?

[Anonymous No.14821715]

>>14814238
there would be another "series" similar to lanthanides and actinides if we discovered more elements. we just haven't gotten to the next "row" of the periodic table yet

[Anonymous No.14821952]

https://youtu.be/38aoxRrL1IQ?t=66
Does this sound like bullshit to anyone?
Mustard oil is a less refined type of oil but I'm wondering if this makes any sense scientifically

[Anonymous No.14822007]

>>14796587
Given a decimal representation of a number, how do I determine whether or not it is irrational?

[Anonymous No.14822040]

>>14821531
>>14821545
>>14821585
So I've found that 1 could work for A and 2 work for B, would that work?

And I've carefully drawn out steps and explanations showing why it would be less than or equal too, which is what I'm guessing his old fat ass wants

[Anonymous No.14822069]

>shit innawoods
>wipe with leaves
>go to river to wash
>shortly after
>butt itchy
>days later
>still itchy as fuck
>used regular leaves
>didnt use poison ivy nettles etc
wtf do I do?/??

[Anonymous No.14822083]

>>14822007
if there is a decimal representation it is rational
If there is not a decimal representation it may still be rational, i.e. 1/3 has no decimal representation but is rational
If the closest approximation in decimal is repeating then it's rational, i.e. .333.... or .145145145...
if the closest approximation in decimal is just random digits going on forever like .389578575928572938572966960... then its irrational

[Anonymous No.14822112]

>>14822069
Butthole infesting swamp amoeba. I've seen this before. It might be too late, I'm sorry

[Anonymous No.14822120]

>>14822112
what
my whole butt is itchy not just butthole

[Anonymous No.14822137]

>>14822120
>it's already spread to the whole ass
damn, so it is too late

[Anonymous No.14822147]

>>14822137
wtf

[Anonymous No.14822218]

does anyone know where I can find examples of this process using numerical data?
I'm trying to do this will some airfoil pressure distribution measurements but I'm not getting the right stuff. I asked my professor and he just directed to another book that has this exact same shit in it
there's clearly something up with my script
but I can't figure out what and it's awfully frustrating because programming isn't enjoyable

[Anonymous No.14822234]

>>14820630
>>14820632
The question may be asking for the answer to be limited between 0 and (pi)/2, either directly or through some indirect constraints.

[Anonymous No.14822251]

>>14822218
actually, I don't even think anything is wrong with my script at all. I think I'm just struggling to use the data correctly
it's meant to be non-dimensionalized but there's no indication of what it's non-dimensionalized with respect to which is silly. any examples are still appreciated

[Anonymous No.14822279]

>>14821512
what the fuck is "lg"

[Anonymous No.14822408]

>>14822279
Typically it's used for base 2. I don't like it either.

[Anonymous No.14822687]

>>14822040
>So I've found that 1 could work for A and 2 work for B, would that work?
Doesn't seem right, consider when n=10 then
A*log10(10) = 1
B*log10(10) = 2
But
lg(10) ~ 3.32
clearly B*log10(10) < lg(10)

Are there any restrictions on n? if n is a positive real number then A and B can't exist. It's only solvable for the cases when n >= 1 or n <= 1

[Anonymous No.14822709]

>>14822687
Have you tried putting
[eqn]A = B = \log_2(10) [/eqn]
?

[Anonymous No.14822759]

>>14822040
[math] A \log_{10} n \le \log_{e} n \le B \log_{10} n \\
\implies A \log_{10} n \le \dfrac{\log_{10} n}{\log_{10} e} \le B \log_{10} n \\
\implies A \le \dfrac{1}{\log_{10} e} \le B \\
\implies A \le 2.3 \le B[/math]

[Anonymous No.14822783]

>>14822759
replace ln with log2 but whatever, misread that stupid lg notation

[Anonymous No.14822846]

>>14822007
If it "ends" with a repeating sequence (including repeating zeroes, i.e. a terminating decimal) then it's rational, otherwise it isn't.

E.g. x=0.142857142857...
=> 1000000x = 142857.142857... = 142857+x
=> 999999x = 142857
=> x = 142857/999999 = 1/7

This is true for any base. A rational number will end in a repeating sequence in every base, an irrational number will produce a non-repeating sequence in every base.

[Anonymous No.14822950]

>>14822846
>non-repeating sequence
then its not a sequence

[Anonymous No.14823161]

>>14822950
What? Any injection from the naturals is a sequence