/sci/ - Science & Math

>>>>9564391
>>Ah, you mean intensional vs. extensional *type theories*, not *proofs*?

>>>9564435 (You)
>Wait, what's the difference?

A proof is a proof, a type theory is a type theory. I suppose you could call a proof intensional or extensional to refer to what kind of theory it's a proof within, but I've never seen that before.

if I switch from cs to math (I have a grade average of B), will I be able to make it?

>>9564511
That depends if you are better at math than CS.

Generally speaking CS is a heavier courseload of easier work. Math courses don't force you to do much work but the material itself is more demanding.

Did mods delete the other thread due to anime spamming or what?

>>9564622
probably

Why does integration feels so much harder than differentiation in most cases?

>>9564732
I wouldn't know. I'm a mathematician after all, not a "computer scientist".

>>9565065
>I'm a mathematician after all, not a "computer scientist".
Mathematicians use "we", not "I".

>>9564732
Because integration requires global data of the function while differentiation only needs local data.

Will he ever publish?

How to sketch and visualize vector functions? I'm studying multivariable calc and this is the hardest part to me

Any tips?

How would I go about proving that Ɛ'(U) is the dual space of C^∞(U)?

I know that I need to show that F ε Ɛ'(U) extends uniquely to a continuous linear functional on C^∞(U) and if G is a continuous linear functional on C^∞(U) , then G|Cc^∞(U) ε Ɛ'(U).

Please PLEASE help me anime math gods.

>>9565072

We am a mathematician after all, not a computer scientist.

>>9565689
The accumulated filth of all their analysis and applied mathematics will foam up about their waists and all the whores and physicists will look up and shout "Please PLEASE help me anime math gods!"... and I'll look down and whisper "No.”

>>9565667
vector fields

at some point in space your function gives you three values, which correspond to the magnitudes of a vector in your basis, therefore by plotting multiple such points you will obtain vectors showing you some "streamlines" that would take some test particle and flow it throughout the field like a river

modify dimensions from this most important case and you can visualise anything

group theory exam today, I think I'm fucked. wish me luck

Is he a hack?

>>9565695
>applied "mathematics"

>xd anime and math
>xd go bagg to rebbit
>xd i gate fisics

9565799
Stop being a retarded newfag and people will stop telling you to fuck off to where you belong.

>>9565806
Do you need to swear?

>>9565806
I think it's only (you) anon.

>>9565806
>i'm fresh out of reddit the post

[eqn]\begin{bmatrix} 1 & 1 \\ 1 & 0 \end{bmatrix}[/eqn]
*blocks your linear algebra*

>>9565816
In what fucking way you brainlet?

>>9565819
wrong matrix, don't bully me pls
\begin{bmatrix} & 1 \\ 0 & 0 \end{bmatrix}
*blocks your linear algebra*

last attempt at this shitpost
[eqn]\begin{bmatrix} 0 & 1 \\ 0 & 0 \end{bmatrix}[/eqn]
*BLOCKS YOUR LINEAR ALGEBRA*

>>9565820
You failed twice, impressive

>>9565799
You forgot
>xd I am so depresd
>xd I wannuh suk a cock

>>9565824
>>9565823
third time's the charm x

>>9565806
>>9565815
>>9565823
Your people are not welcome around here. I suggest using >>>/r/eddit/.

>>9565799
>>9565826
See >>9565830

>posts math content
>"reee get out!"
lmao, keep posting, this is entertaining.

>>9565833
Who are you quoting?

>>9565799
>HURR LET ME POST PHYSICS IN A MATH THREAD

>>9565833
>reee
>lmao
see >>9565830
>>9565843
>HURR
>LMAO
see >>9565830

>>9565843
It's not my fault anything that involves vector/tensor calc, representation theory, PDE and the like is treated as physics here.

>he can't into group theory applications to QM
massive brainlet detected.

>>9565850
I've never seen representation theory treated as physics here, what posts are you referring to?

>>9565850
>vector/tensor calc
>PDE
Please refer to the proper board for discussing physics.
>>9565854
>QM
I'm sure they would like to discuss that with you in the physics threads over at >>>/toy/.

>>9565858
Well one time I posted some shit about the Lorentz group, and everyone got triggered. Though, now it's mainly this shitposter
>>9565860

>>9565865
Redirecting people to proper discussion boards is shitposting? Is your severe level of brain damage due to physics?

>>9565868
A yes, /toy/ the place for discussing mathematical physics.

>>9565868
best not to argue with "it" m8, gets nowhere. Pretty sure it's mentally ill.

>>9565872
It doesn't matter what adjectives you decide to attach to "physics". That won't make /mg/ an appropriate place to discuss it. I recommend using >>>/toy/ or trying to create your own "mathematical physics" imageboard.

>>9565878
>I recommend using >>>/toy/ or trying to create your own "mathematical physics" imageboard.
Mathematicians use "we", not "I".

I bet this handsome motherfucker triggers the lot of you

Explain the relation between math and sissybois right now.

>>9565887
People usually don't get "triggered" by animals.

>>9565695
>I don't know how to answer your question

>>9565905
Who are you quoting?

>>9565906
The post I linked

>>9565909
As a mathematician we would not use "I" in our post, what you quoted with an "I" in it must be in a different post.

have this:

a1 = {2;3}
a2 = {3,5,7}
a3 = {1,7}
a4 = {3,8}
a5 = {9,3}
a6 = {6,4}
a* = {...}

As you can see, 3 is them most common number. What would be the formula to find it? I assume it exist, so wiki link work too.

>>9566069
>a* = {...}

>>9566073
...what?

>>9566081
What is "a* = {...}" supposed to mean?

>>9566094
anything that first the criteria, imagine

a7 = {1,5};
a8 etc

It was just an example, you can take first 6

>>9566069
There's no "formula" for such a thing that would be anything other than a trivial rephrasing of "most common number".

>>9566069
>>9566112
And it's also not even necessarily well-defined.

>>9566112
So in other words you are stating such task cannot be solved by math (any kind of math, any category)?

Imagine context: an apartments house of 100 rooms. Each occupied by 1 resident. In March, between march 19 march 25, there is an apartment-wide meeting but the organizers need to decide which day of a week to pick up so they cover majority of the people.
So, 7 days a week. They call each one and ask which day(s) these find acceptable. One guy says Monday and Friday, so:
a1 = {1, 5} (2 days out of max 7)

This is context. Now, there are 10 or 100 variables, for example, we need to do math to find out the most common day for each.

>>9566125
you could define a function [math] f: \{1,2,3,4,5\} \to \mathbb{N} [/math] with [math] f(i)= \text{# of people free on day }i[/math] and then the most common days to be the set [math]\{j \mid f(j)=max_{k=1,2,3,4,5} f(k)\} [/math], but this is just a restatement of 'most common elements'

>>9566125
>So in other words you are stating such task cannot be solved by math (any kind of math, any category)?
No, he is saying that the formula is obvious.
You might be looking for an "algorithm", a computation for that maximum.

>>9566142
so that
>>9566141
would be an algorithm?

>>9565887
Nope, big fan here. I don't even work in his area but you gotta recognize raw talent

>>9566166
>would be an algorithm?
No, that is a "mathematical description".

An algorithm is usually stated in some form of "pseudo programming language", in which the steps to acquire the wanted results are described.

>>9566175
Damn i was hoping for some magic "math function" where you crunch some numbers and get an answer, at least approximate.

I can write simple for loop in prog. language no problem

>>9566172
How is "raw talent" in things unrelated to mathematics somehow relevant to this thread? Maybe we should start discussing raw talent in music and painting here as well?

>>9566181

Well, think about it: How would you even answer the problem without at the very least reading every single letter, since you don't have any other assumptions about the distribution of the numbers in the set?

The best you can do is scan over all of them and keep count. This is an information-theoretic lower bound of Omega(n) assuming n elements.

>>9566181
Why did you think that could work?
Looking at every set once is the trivial solution, although there is some trickery you could do to speed up the process.

> at least approximate
Quit your loop after a few steps, then you have a "good guess" (although it could be completely false) at what the maximum could be.
eg. just look at a1 and a2, the result will be 3.

>>9566188
You don't necessarily need to look at every element, if one number turns up often enough you can terminate early.
But to be honest there is little point in actually doing it.

>>9566199
>Why did you think that could work?
I dunno, some math magic like, summarize all values for each An and then divide by some magic stuff so the final results will be close to most common number

>>9566234
>I dunno, some math magic like, summarize all values for each An and then divide by some magic stuff so the final results will be close to most common number
But that is just as complicated as just going through the list, I am not aware of any magic that could make the computation easier.

>>9566240
>But that is just as complicated as just going through the list, I am not aware of any magic that could make the computation easier.
I think it is easier to do a sum of number and then division on calculator rather than going through 10+ entries and trying to determine most common number manually. 10 may be not a big deal, but 50? mechanical math operation with calculator is simpler

Anyone else getting fucked by complex analysis? Shit's hard, yo

>>9564732
Same reason walking backwards is harder than going forwards

>>9566182
Nigger do you even know how Arnold is?
https://es.m.wikipedia.org/wiki/Vladímir_Arnold

>>9564732
They are just harder to compute analitically. But they are pretty easy to understand.

>>9566263
Well, that might be the case, but calculating the average won't help you much here.
I doubt that you can do much beyond the trivial, counting how many time each number appears.
Anyway, that is what computers are for, I suggest that if you are facing this problem in realty a computer will, with a trivial algorithm will give you the quickest answer.

>>9566289
>but calculating the average won't help you much here.
Dont be silly, sweetie, the average was just an example.

Question was theoretical, there is no task at hand, I was just curious if some gurus of Calculus (math analysis) can think of something that can produce desired results.

>>9566327
>I was just curious if some gurus of Calculus (math analysis) can think of something that can produce desired results
This has very little to do with calculus.
If you are interested in an efficient algorithm, then go ask people who do CS.

Will applied math + statistics degree get me a job? My dumbass parents say no cuz it will be automated in the future and want me to do cs

>>9565777
No, but his ego is bigger than even Motl's and much more fragile.

Is there any way to prove that
[math](a=b)\iff (a+c = b+c)[/math]
from the field axioms of the real numbers? (or for abelian groups in general)

Also, even in proof-heavy calculus 1 courses we use stuff like

given that a=5
then the equation a + 6 = x is equal to 5 + 6 = x. Why is that so?

>>9566354
Motl has never been wrong, he earned his ego

>>9564732
>>9565065
it's funny because it is the opposite for a computer, i.e., finding integrals is easier.

>>9566506
I suppose you know that the general procedure is to add (-c) to both sides and associate and whatever. It's called the canceletion law and it's valid even for non commutative groups. But your question seems about the "preservation of equality". Assuming you are going with spivack, this comes from tricotomy of the total order ir whatever axioms you are using. If you are going even more specific, the equality is equality of sets, and you can construct the real numbers just using set theory. But jusy finish chapter 1 quickly, as it's just a way to introduce proofs.

>>9566506
>=>
>a=b
>add c to both sides
>a+c=b+c
><=
>a+c=b+c
>cut c from both sides
>a=b
>qde
no need to thank me

>>9566534
Not using Spivak as "The Book", but I definitely check it for some definitions and obviously solve the problems.

How can you add (-c) to both sides? Doing that results in a redundant proof, since that's what you want to prove.

I know about the tricotomy of the total order, a>b, a=b or a>b. But how that results in being able to "insert" equivalent values on the terms of your equation?

Basically, why (4/2)+x = 1 can be expressible as 2+x = 1

>>9566589
I understand that the 'preservation of equality' can be proven through the cancellation law. But how can you prove the cancellation law itself?

>>9566589
Well, what axioms are you using? If it's synthetic approach, you usually start by saying that the order is preserved under addition. For groups, in the abstract, you have that if a=b then ac=bc comes from the fact that the operation is a function from GXG to G, and if that wasn't the case the function would not be well defined.

>>9566605
I'd love some more explanation (or books I could read) on the abstract algebra explanation you gave.

But for the axioms we're using, order axioms are:
1) The order relation is a total order (which, to me, can be proven defining a>b as "the difference between a and b belongs to the positive numbers and thus is kinda forced)
2) If a>b then a+c>b+c
3) If a>b then ac > bc for c > 0

What now

>>9566616
K then, use 2) but insteas of > use = (total order means greater or equal). So just add -c...

>>9566597
>I understand that the 'preservation of equality' can be proven through the cancellation law.
No, it can't. There are plenty of examples of things that don't have cancellation but still have equality. Functions, for example, do not cancel, but if f = g then h o f = h o g.

In the cases where it holds you have to prove the cancellation law, and you do this by not being a jackass going
>hurr a=b but how do I know that a is b

I'm getting a letter of recommendation from a super handsome lecturer, but he's like 45 yo. Does this make him my sugar daddy? Good night, btw.

I got Cs in stats and pre calc in college. I never studied or went to class, but still its embarrassing. I now want to learn data analytics to help with my research job. I know this field requires linear algebra, statistics, and some calc. My plan is to start back in high school math for a refresher then move through working on MITonline courses. Then Ill buy whatever books I need to round out.
Any advice on relearning math? I'm shooting for 2 hours of practice a day until I get up to speed.

>been out of college for 4 years
>left off at calc 1
>have to relearn most of math in a few months
If I fucking cram, is it possible to get myself back into working order?

I messed around with some Riemann sums and limits on Khan, and kinda somehow did things I didn't remember learning.

Hey fags, any grad school kiddos here? What's the competition like? Will I BTFO everyone if I read the canon (Rudin's Analysis, Munkre's Topology, Knuth's Concrete Mathematics, etc) in addition to what I do in undergrad?
>>9567167
What are you trying to test into? You could pass Calc 1 with flying colors in that time.

>>9567153
Start with as high level as you're slightly uncomfortable with, fill in the gaps as you go. If I were you I'd start with a book like James Stewart's Calculus: Early Transcendental as a problem book review. Use Professor Leonard if you're stuck, along with the more well known resources that I asssume you know, like Paul's Notes, Khan Academy, 3Blue1Brown, etc. Try to work into Spivak, Apostol or Tao as soon as you're able, perhaps even in tandem.

>>9566343
Yes, just learn programming too and develop a lively github.

>>9564732
cuz differentiation has the chain rule and integration comes down to finding a closed formula for [math]\sum_{n=1}^\infty f(n) [/math]

>>9566199
>You don't necessarily need to look at every element, if one number turns up often enough you can terminate early.
But to be honest there is little point in actually doing it.

Okay, sure, you're correct. You need to look at least half the elements.

>>9567512
Thanks for the math advice I appreciate it.

>>9567512
>Will I BTFO everyone if I read the canon (Rudin's Analysis, Munkre's Topology, Knuth's Concrete Mathematics, etc) in addition to what I do in undergrad?

>>9567512
stop giving advice
jesus fucking christ you're awful

>>9567512
>Will I BTFO everyone not knowing any mathematics at all?
Sure. I don't see why not.

>>9567851
>>Will I BTFO everyone not knowing any mathematics at all?
Who are you quoting?

>>9567130
>night
Finn whore please go away.

>>9567932
Most rude.

>>9566513
CDF paper

>>9564451
>maths
>>>/x/

Brainlet here, I'm getting 41 and 1/6 while proper answer is 40 and 5/6
Wtf?

>>9568207
>>>/sqt/
Stop posting your dumb shit here

>>9568224
>/mg/ maths general
>Talk maths.
Not your personal thread, sweetie, fuck of.

>>9568227
Since when is "talk maths" a synonymous to "do my homework for me I'm a retarded fucking brainlet who can't do simple arithmetic"? That's /sqt/ material

>>9568233
It is not a homework, I'm asking to confirm is answer is correct. This is the only one that gives me troubles so I'm curious if the answer has a typo.

There are better places to find answer for homework of any kind, retard. Why would anyone go here?

>>9568238
Wolfram Alpha or Symbolab it you autistic fuck, or use literally any calculator, why the fuck would this be the place to ask someone to compute for you? It is /sqt/ material because it's a fucking stupid question, get out of here you child.

>>9568207
>>>/sci/sqt/
Performing trivial computations with "numbers" is not math.

>>9568207
Ask a computer, you could have typed this into google and gotten a result in the same time it took you to make this post.

>>9568277
>>9568243
Fair enough niggernauts, I will fuck off to sqt

>take exam and get stuck on a couple questions
>as soon as I leave the building I figure out the answer to all of them
Should I just buy the helium tank now

>>9568207
Turn them into improper fractions then find a common denominator
Are you in elementary school or something

Can someone explain the Segre embedding?

Consider a vector bundle [math]E\to B[/math] and [math]A\subset B[/math] a subspace. Suppose [math]E[/math] is trivial. Is the restriction bundle over [math]A[/math] necessarily trivial?

>>9568580
of course, just restrict the trivialization

>>9567512
munkres a shit

>>9567512
>Will I BTFO everyone if I read the canon (Rudin's Analysis, Munkre's Topology, Knuth's Concrete Mathematics, etc) in addition to what I do in undergrad?
Are you implying your undergrad does not cover these?

lol

LOL

HAHAHAHAHAHAHAHAHAHAHA

>>9567512
Here's your (you), you tremendous brainlet.

Do you guys hate applied mathematics majors too? You seem to hate everyone and have a surprisingly shitty taste in anime.

>>9568367
This happens to me to often. You need to calm down anon. It's probably your nerves.

>>9568800
>Do you guys hate applied mathematics majors too?
I don't think anyone "hates" fictional characters.

>>9568800
It's easier to chimp out and use the attention to validate yourself instead of learning more.
Pity them and move on.

>>9567819
>>9567851
>>9568705
>>9568711
I don't see why my post triggered you guys so badly, and I don't see how putting extra effort into my studies is a bad thing by any stretch of the word (beyond having a social life or whatever unrelated BS).

>>9568800
recommend me a good anime, I really enjoyed Death Note but haven't seena nyting else

>>9568800
>have a surprisingly shitty taste in anime
This, moeshit plebs the lot of them.

>>9568948
Pic related

>>9568954
am I a pleb for liking deathnote or is deathnote widely considered good?

I come from a relatively extensive cinema background, and Death Note really convinced me of anime having worth as a medium. No other medium could've expressed what Death Note did as well as it did it, imo

>>9569002
the second half of death note is irredeemable

>>9568800
anon, it's literally 1-2 autistic weebs max making 75% of the shit posts, don't put that on all of us.

>>9569056

Newfag here
I want to learn math at home over the summers because the master's I want is math heavy
Where can I relearn everything up to stats, calc and linear algebra? Will Khan Academy be good enough?
Help is appreciated

>>9569070
Yes. Good luck.

>>9569072
That was quick and easy. thanks anon. Math mission begins now

>>9569076
No problem. Remember not to bit more off than you can chew, and be sure to fully understand things before moving on. Perfect practice makes perfect.

>>9569077
This, people can tend to be overambitious when self studying.

What are you guys currently pursuing/have a degree in and what do you plan to do as a career?

>>9569040
>irredeemable
I agree, but the first half was stellar. I wish they'd produce an alternative second half desu

>>9569085
How do you know if you're victim of this?

>>9569105
maths, idfk. It'd be cool to work at Jane Street tho, or get a comfy phd

>>9569105
Maths major with a theoretical CS minor. Looking for some kind of programming field that is also quite mathematical. Thinking of something like security/cryptography.

Pic related is the answer to chapter 1 problem 19, of Spivak's Calculus. Here you can see more of the question:

>https://math.stackexchange.com/questions/1329759/michael-spivaks-calculus-chapter-1-problem-19
>https://www.physicsforums.com/threads/spivaks-calculus-4ed-1-19-schwarz-inequality.585714/

what I fail to understand is how the 'lambda' symbol was just dropped completely from the solution. I don't understand how I go from an equation not having a solution, to dropping one of it's terms and setting up an inequality. I complete the previous exercise 18a) that is referenced, along with all previous questions. I understand the algebra of the inequality after the lambda is dropped, but I'm not sure how I would do that, and more importantly, what my motivation for doing so would be.

>>9569150
>I don't understand how I go from an equation not having a solution, to dropping one of it's terms and setting up an inequality
use the quadratic formula

>>9568948
FLCL
evangelion
madoka magica
nichijou
my hero academia

>>9569161

>>9569152
Can you demonstrate how you would go about doing so?

>>9569139
type theory links foundations of programming with foundations of math
check out Software Foundations for a course/book about 100% formal reasoning in a computerized, type-theory based setting
https://softwarefoundations.cis.upenn.edu/

>>9569166
wait nvm, I think I'm getting it

>>9569164
sorry should I have included boku no pico

>>9569166
>>9569173
>>9569152
>>9569150

Pls gib halp

>>9569205
use the quadratic formula

>>9569114
>How do you know if you're victim of this?
1. You dont understand what you're doing: any of: you're just reading statements and proving them without thinking about what they mean or imply, or can't do most exercises, or don't follow a proof at all. Remember: being able to prove or compute something doesn't mean you understand it.
2. You're not looking back: for every two steps forward, take one back. Reread what you've worked through to make sure you grasp what the book is trying to expose.
3. You don't know where it is headed. If you don't have a clear motivation, you will not see what the point of it is or why something is defined that way.

I know because they've all happened to me and even lecturers don't make you see well. For example, I had an algebraic number theory class and only when I began studying for the final (and only) exam, did every piece start falling together and everything just clicked - i only wish i had looked over the motivation before so that i would have learnt it better.

>>9569221
seconding all of this very hard

>>9569209
can you demonstrate please? I'm absolutely at a loss here.

I set [math] a = (y_1 ^2 + y_2 ^2) , b = -2(x_1 y_1 + x_2 y_2) , c = (x_1 ^2 + x_2 ^2), x = \lambda [/math]. Is that right?

>>9569254
>I set a=(y21+y22),b=−2(x1y1+x2y2),c=(x21+x22),x=λ. Is that right?
Yes

>>9569254
Yes, and there's no solution iff
b^2 - 4ac < 0

>>9569254
So then the quadratic equation would like:

[math] \lambda = \frac{-2(x_1 y_1 + x_2 y_2) \pm \sqrt{(-2(x_1 y_1 + x_2 y_2))^2 - 4(y_1 ^2 + y_2 ^2)(x_1 ^2 + x_2 ^2)}}{2((y_1 ^2 + y_2 ^2))}[/math]

>tfw no tex preview b4 posting

>>9569262
there's no solution iff b^2 - 4ac < 0
OH SHIT

that's the missing link I was searching for, thanks anon. The whole thing makes sense now. I understood the algebra of it, but not the motivation or utility of it until you said that.

Serious question: in what career that pays more than 8.25/hr do people use NUMERICAL SIMULATION and their job is important?

>>9569262
Ok, still a little confused. b^2 - 4ac < 0, then there's no solution.

But how did the author arrive at (-b/a)^2 - (4c/a) < 0 ?

>>9569263
you can use something like mathb.in to preview

>>9569266
Rocket Science at NASA

Doing numerical simulations until everything works out is much cheaper than building a shitload of rockets with slightly different parameters and trying them out.

>>9569263
>>tfw no tex preview b4 posting

>>9569271
Multiply by 1/a^2. This preserves the inequality since it is strictly positive.

>>9569221
>You dont understand what you're doing: any of: you're just reading statements and proving them without thinking

this is the best description of my experience with studying maths for 4 years

also:
>You don't know where it is headed.

>>9569304
I see, thanks. I gave up too early on the algebraic manipulations. I'm going to have to think about this problem and the implications for a bit anyhow

>>9569114
>Jane Street
Interning there in summer 2015 made me avoid fintech and go into avionics.
Same pay, work 8 hours a day, 5 days per week with 3 months paid leave. The shit i do is actually put into practice and is held up to at least some standard.
t. CS retard doing formal verification at Saab

>>9569380
what was so bad about it?

>>9569309
you're doing it wrong.

Another dumb question.

I'll screenshot the answer and expand on what I've done so far in the next post.

>>9569423
>>>/sci/sqt/
Go over there and ask please

>>9569423
I don't understand at all how I'm supposed to get 2 on the right hand side, while getting the numerator on the left hand side.

In aimless attempts at striking gold with algebraic guesswork, I found a common denominator for the fractions on the right hand side, and was left with a fraction of the form [math] \frac{x_1 ^2 (y_1 ^2 + y_2 ^2) + y_1^2(x_1 ^2 + x_2 ^2)}{(x_1 ^2 + x_2 ^2)(y_1 ^2 + y_2 ^2)} [/math].

I understand from the top answer here:
>https://math.stackexchange.com/questions/1329759/michael-spivaks-calculus-chapter-1-problem-19

That the numerator can be factored further, but I take issue with the top answer for two reasons:
1) The denominator was not squared as it should've been, since we begin with x^2 + y^2, where x is an atrocious fraction with a square root in the denominator.
2) The notation is not something that Spivak has covered yet, and while I understand summation notation somewhat, the indexing was a bit off putting as it doesn't sync up with Spivak's answer (I also prefer to approach text in a self-contained fashion, using only what has been given).

There's must be some algebraic tricks lying here somewhere, but how do I find them?

>>9569437
See
>>9569434

>>9569434
>>9569439
Why are math questions not allowed in /mg/?

>>9569442
They are, just not dumb ones like this. We're not here to help you with your homework, go to /sqt/ for that. This is mainly for discussions and advice and so on... /sqt/ was iiterally made for dumbass questions like yours so take advantage of that and don't flood us with this garbage

>>9569442
They are allowed for the discussion of math topics, that, questions that have enough in them to bring out a discussion. That inequality has like 100 proofs and each proof is in like another 100 different textbooks, so yea it's a stupid question that gives nothing, as you are not asking about the inequality per se, but about the algebraic manipulation in the proof. So fuck off.

>>9569447
Why so mad? /sqt/ is generally a bit slower/flooded with much dumber questions, and it's not even homework, it's just something I'm trying to work through.

>>9567512
I'm trying to get into doing my math series. So I pretty much just trying to get ready for calc 2. I took calc 1 already, and I'm just trying to resharpen my skill set for the next one.

>>9569451
>That inequality has like 100 proofs and each proof is in like another 100 different textbooks
Would you mind supplying me with some?

>>9569455
>what is google
https://www.google.com.mx/amp/s/onionesquereality.wordpress.com/2013/09/25/some-proofs-of-the-cauchy-schwarz-inequality/amp/

>>9569451
>>9569447
and who are you two to decide what is / isn't allowed in an anonymous fucking /mg/ thread anyway? it's quite clear that there is no objective set of rules posted regarding this, so how do you expect people to know other than by flaming them when they post problems?


and further, why do you care? at least it's discussion, you can just ignore it if you don't want to answer ofc

>>9569467
In my opinion I believe it's cancerous to trear mg as sqt
>who are you
Who the fuck are you? Im calling you a faggot if I want so. If the community is against me, well though shit, but I know a lot of anons hate spoonfeeding to retards who can't use a search engine. We can always type up some pasta saying what are the "rules" of the general.

>>9569467
>and who are you two to decide what is / isn't allowed in an anonymous fucking /mg/ thread anyway? it's quite clear that there is no objective set of rules posted regarding this, so how do you expect people to know other than by flaming them when they post problems?
We're not a "you".

>mfw /sqt/ nigglets come in here

>>9569473
>it's cancerous to trear mg as sqt
I didn't imply this, I was only speaking of a strictly maths /sqt/. I'm sure you think that's cancerous too though, but I don't particularly think it is. I don't mind helping other anons here when they post and I'm able either.

>who the fuck are you?
I'm not the one acting as if I what I'm saying is backed by some sort of rule or authority, so your point is moot. I'm not asking for spoonfeeding and I've searched extensively already, most of the proofs omit the algebra ofc, so I'm not turning up decent help despite that.

>tfw this debate is more cancerous than shitposting a basic algebra question

Brainlet here. I am wondering if it is possible to prove the following postulate:
"For every odd number |n|, there exists an even number |n| + 1 which has a number of factors equal to or greater than the number of factors of |n|."

(I'm not sure if I'm phrasing that properly, but essentially I'm trying to say that 2 has >= factors than 1, 4 has >= factors than 3, 126 has >= factors than 125, etc etc..)

>>9569475
You're not a human being?

>>9569486
It's false.

>>9569437
>>9569423
nvm

>>9569485
Stack exchange is literally made for helping newbs. Read the /sci/ sticky. /sqt/ was created to contain all the faggots who when stuck on some problem made a whole new thread. While it's true that there should be a pasta for math general, it's implied this is not a thread for that purpose. It's like all the faggots in /g/ who can't post in the thousend generals they have, for tech support. And irregardless of that, I know you haven't looked exstensiby, cause you just have to look for cauchy-schwartz inequality in google to find a thousand proofs

>>9569500
Dang okay. Thank you Anon.

>>9569512
Nothing in the sticky opposes what I did (it's not """""homework"""").

I had looked for about an hour before posting, and this was after trying it for an hour or so. My problem ended up not lying in the proofs or algebra though, it was a misunderstanding of what Spivak meant when said "addition" (not that it matters).

I don't know why you care so much but you're allowed your own opinions and preferences, personally I don't mind and I think it keeps the thread active and alive. It's also orders of magnitude less gay than stack exchange and reasonably quick (especially /mg/ over /sqt/).

>>9569486
to elaborate on >>9569500, if you mean prime factors, note that 16 has only 2 as a prime factor while 15 has both 3 and 5

>>9569447
>>9569451
>>9569467
>>9569473
>>9569475
>>9569485
>>9569512
>>9569523
you all realize that this stupid fucking argument is clogging up /mg/ _much_ more than the original question[s] ever did, right?

>>9569523
But I mean if I'm truly in the minority here I'll keep them contained at /sqt/. But at what point does a math question become too advanced for /sqt/ and it merits a post here, in your opinion? Or is that never advisable?

>>9569529
that's why I said >>9569485:

>tfw this debate is more cancerous than shitposting a basic algebra question

turned out it was a basic reading comprehension question instead though

>>9569525
I did not mean prime factors. I'm trying to establish an explanation for why randomly selecting two integers is 3 times more likely to give you an even product when multiplied together than an odd product.

Logically, it follows that this would be the case since EE, OE, and EO all generate even products while only OO generates an odd product (this can also be 'proven' or demonstrated with any defined number set with a beginning and end so long as there are an equal number of even and odd numbers in that set, but I'm trying to extend it to a generalized set of all integers) but I'm hoping for a more rigorous proof.

>>9569533
sorry, i was just scrolling past the argument, not reading carefully

>>9569539
probabilities related to picking integers at random are pretty fucked and subtle, but the simple explanation you gave would suffice if you just rephrase as "given some fixed upper bound N, then picking random two random integers less than N..."

>>9569263
4chan X my friend

>>9569531
The point is not the degree of complexity, but what discussion entails. I can ask about some hard, but typical problem in, idk, differential geomtry. It just takes one person to answer that make it the thread pointless. If you actually want to discuss concepts, explore them, or conjecture, then you have a thread. Understanding the details in thhe algebra of a proof is just tedious symbol manipulation, but the C-S inequality is a real important thing and asking about understabding the meaning makes sense. I suppose that the sticky should change to "/sci/ is not your solution's manual or personal tutor". I mean, I know newbs don't understand how meaningless certain detaild are compared to others, but don't delude yourself that symbol manipulation (elementary algebra) is in any sense some weird concept that needs peopke here explaining.

>>9569549
Gotcha. I think the end point I wanted to reach was something along the lines of "when taking the set of every even integer and comparing it to the set of every odd integer, there are three times as many factors in the even set than the odd set" except that is stupid and doesn't make sense. I understand the logic but am hoping for a more formal proof than a functional rule/definition.

Thank you again for your help, I think I'm going to read up a bit more on this stuff to see if I can understand it a bit better.

>>9569563
Getting help with problems and having good discussion do not have to be mutually exclusive.

>>9569573
No, and it could get pretty arbitrary which are which, so I understand the complication, but my experience as a tutor and teacher shows me the difference between people who wan to really understand, and lazy cunts who want to be spoonfed the messy details.

>>9569581
There is no reason to think I was looking to be spoonfed.

>>9569581
Also, you're backtracking in your argument.

I'm a medfag trying to delve into maths in my free time
I need to know if it is normal to struggle a lot with formalism and notation. Most of the difficulties come from "translating" what's written, what does the symbols mean, what's the information in the message
I always feel like I need to reformulate the mathematical expression and statement in a more natural language if I want to understand it

The problem especially struck me when I try to understand a proof. I spend more time trying to understand what means each expressions than to understand the reasoning

>>9569596
this is completely normal and often referred to as lacking "mathematical maturity". the solution of course is more rigorous math.

>>9569596
also math notation is often intended to be really dense (as dense as possible). sometimes a paragraph takes me a whole half hour

hey mathfags, which one would be easier

barely passing math courses, or getting good grades in a cs degree to do a masters?

asking for a frien

>>9569613
barely passing math courses in a mathematics major, I mean

>>9569569
No problem. Good luck!

>>9569586
If you can't plug and chug and do tedious, but straightforward algebra, you should home your algebra skills. Everythinf you posted had the solution. I undrstand you can fuck up on trivial things, but you literally had everything tl conclude. The point is the answer would have been telling you to open your eyes or write it for you. It was a dumb fucking question, no matter how you look at it.
>>9569593
Lol, my doubt comes from people who ask dumb shit even when they want to learn. Like all the QM pop sci threads, that I'm not sure if it counts, i.e., non formal discussion about formal topics, which is much more different from "guys wtf how did he pluged abd chugged this".
An example of someone who clearly has not developed a mathematical maturity, but still manages to do a great question is
>>9569596. I'm sounding autistic explaining all this, but it's because all the retarded fucks like you who can't understand the difference between posting a stupud meaningless question with no POSSIBILITY OF DEEPER DISCUSSION, and something like
>>9569596
Which I can respond that it's always nice to bring a geometric intuition to stuff you can, or bring it to a different perpective in general and see what the symboks mean there.

>>9569596
Don't fret too much, this is normal. Like someone else said, it means your lacking "mathematical maturity" and it will improve over time as you do more maths. It really is like learning a language, and over time you will feel more comfortable with dense notation, and even lose the need to "translate". You will understand the symbols independently of their English translation.

The best way around it is to keep going. If something gets too hard, don't be afraid to drop down a level, and find an easier book. Also, you develop maturity fastest by actually attempting and solving problems. Reading alone will not be enough.

I developed the most maturity after going through Baby Rudin -- tackling tough books like that is a part of your "upbringing" so to speak

do you use a dot or a comma for decimals?

>>9569629
>If you can't plug and chug and do tedious, but straightforward algebra, you should home your algebra skills. Everythinf you posted had the solution.

Yes, I was struggling at getting at the solution algebraically, not because my algebra skills were lacking but because it was algebraically impossible to arrive at the answer, it was a misreading of the question. Had you even looked at it, you'd know.

>my doubt comes from people who ask dumb shit even when they want to learn. Like all the QM pop sci threads
I wasn't making a thread, I was posting a math question in a math thread on a math and science board.

All your points are moot, m8.

>>9569670
I was calling you a dumb shit, but the point that you coukd have realized this by posting it in /sqt/, shows that is unecesarry, and for the second thing I was talking about examples of questions that are low level, dumb and ill posed that still can lead to discussion, not that it was a thread. The point of thay post was to show you how ridiculous is to explain to you why your particular question is shit and cancerous, even if it should be pretty clear. I could post every problem from my study guide in lie algebra and use all the autists here as a solution's manual, and yea it's fucking math, but it should be obvious why a low effort shitty question shouldn't be well recieved based on the actual discussion you can get. If the problem is interesting as shit, may be I wilk share it, but with the intention of sharing some cool shit, not to ask people to solve my shit. Again, we need a pasta so you fucks can go to/sqt/ and stack exchange.

>>9569647
fractions

Lads, I'm in contact with an amateur theorist who has, to put it briefly, composed a thesis that undermines the foundation of mathematics. We're having college mathematicians looking at it soon, and if we can't get a response proper we'll go up the ladder to the Professors etc.
I'm not going to share much just yet, but hopefully things'll work out and you'll all hear about this. I'll keep you posted as opinions come in, (feel free to screencap) but I'll try not to bother you too much.

>>9569695
how do you write PI then?

>>9569702
a LOT of fractions

>>9569702
pi/1

>>9569691
Those are you opinions and preferences and that's fine.

But it's not your board. I thought the post was fine, and you seem to be the only one sensitive enough to get triggered by it. Personally, I'm ok with math questions in a math board so long as the poster is putting in their best effort on their end and demonstrating that in the post and replies.

>you could've have realized this by posting it in /sqt/, shows that is unnecessary

I didn't know I was misreading the question until it was in hindsight, had I known it was so simple I never would've posted in the first place ofc.

>>9569613
>>9569617
barely passing math classes with no masters would probably be much easier, but it depends on the material and instructors.

>>9569724
thank you for the information, friend.

>>9569730
why is your friend (you) presented with such a decision though?

>>9569741
I have the option to do a bachelor of "Computer science and pure math " But I'm not sure if I want to do it since I'm not sure I would be able to have the grades to do a masters. So I think I'll just go with computer science only. I already did the equivalent of a computer science minor. pure math still fascinates me tho.

4th year courses offered by my uni

Is there anything important missing?

>>9569747
nothing wrong with having hobbies, CS is far more lucrative from a monetary standpoint, and it enables you to incorporate some maths into your job, and rewards those that have the maths skills.

I'm going for a maths bachelors cs minor personally, but I hope to counteract that with a lot of projects and activity on github in case maths doesn't work out

>>9569758
>maths bachelors cs minor
interesting choice. Did you consider going to grad school?

>>9569748
>6 courses in a semester

I would kms

>>9569768
It's optional and people usually pick 4 per semester

>>9569697
Those guys are always cranks

>>9569846
>>9569697
found him >>9567997

>>9569853
1*1=2 != 3
Terry trivialises it past the point of plausible axiomisation, but effectively it's similar

>>9569846
He does agree with Cantor, he thinks that Cantor's original work has been bastardised by misinterpretation

>>9569748
>4th year
>low credit courses in:
>topology
>hilbert spaces
>combinatorics

wew lad what brainlet uni do you go to?

>>9569901
university of ilorin

>>9569901
noname university in small town (not in USA
Gov pays me to go

>>9569901
Also the only courses with more credits than that in the entire university are full-year law/art courses or Master/Phd programs

>>9568945
>extra effort into my studies
Learning stuff you should know in your first year is not ``extra effort".

>>9568954
>moeshit
This is not well-defined.

>>9569647
Comma, obviously. And that is only when I use an online bank.

>>9569647
We don't use so-called decimals in mathematics.

>>9569417
Except for employee abuse, which was universal to whole company, all the reasons why it made me avoid fintech were related to their software engineering practice (rather lack thereof)- it's mind-boggling how perhaps the biggest industrial proponent of ocaml is so reluctant to take advantage of its environment (mainly talking coq).
Maybe as a quant it's at least interesting work, though i don't enjoy the specific areas of math used in fintech, but the CS side is terribly boring and unrewarding. In comparison, working at Saab is like a dream come true for a verifag- everything and its mother is specified, proper engineering practice is enforced, management tries to push verification for anything they can, people get in trouble for touching keyboard with empty whiteboard or papers, access to pretty much any journal and financial encouragement to read articles.

>>9570122
sounds cool. i remember some applied maths phd on /g/ who did quant work and was trying to convince his boss to switch most of there c++ and haskell to ocaml in part because coq.
what education do you have?

Should I even both studying for my intro to number theory midterm?
I feel like there's no way there can be some number of problems that fit into 50 minutes that are difficult to find proofs of, especially since the classes won't be curved.

>>9569380
>>9570122
>>9570140
Fuck off to the >>>/g/hetto/.

>*blocks your path*

https://en.wikipedia.org/wiki/Riemann_hypothesis

>>9570170
meant to quote >>9570156

>>9570140
Coq is great, still don't understand why Jane Street avoids it when their models are fully specified and translating it to coq is a matter of few days. Along with the fact that considerable portion of their code is ocaml, this gives them the very rare opportunity of having formal verification with very low effort.
I have PhD in CS (dissertation was on thread-modular synthesis for verification of concurrent lock-free algorithms) and MSc in math (thesis was on KK-Fredholm operators in symplectic geometry).

>>9570349
>>>/g/hetto/

*blocks your path*
[eqn]e^{\frac{i\tau}{2}}=-1[/eqn]

why are women allowed to do math?

>tfw couldn't figure out how to compute this shit in an exam today [math]\int_{-\pi}^{\pi}|e^{i\alpha x}|^{2}dx[/math]
>mfw I realized how fucking stupid I was

I think I'll just drop out now. I never want to see my prof again.

>>9570577
Depends. Women (male) or women (female)?

>>9570621
2pi

>>9570621
Why are you telling us about your engineering exams?

Math is unnatural and profane. Our fingers weren't made for this fancy line drawing, neither were our minds ever to have those abominable, hellish thoughts. It is in the Bible

>>9570773
It was a mid exam for baby Fourier analysis. I even used that same result in some trivial aproximation earlier in the test, I can't believe I somehow totally blacked out on this. All things considered, I should probably enrol to some shitty polytechnic based on this performance.

>>9570718
Yeah, it's very clear that |e^(iax)| = 1. Everyone should know that by heart after highschool.

>>9570122
fucked up if true

>>9570164
found the platonist

>>9570790
math manifests itself in physical form every moment of our existence.

>>9570814
Sorry, I'm not mentally diseased.

>>9570794
>Everyone should know that by heart after highschool.
Perhaps everyone who will be studying engineering should. I see no reason for any mathematician to know or even care about this.

>>9570850
>a mathematician not knowing that the modulus of a point on the unit circle is 1

Pull the other one, anon

In your professional opinion as math aficionados, how often do you think it's healthy to drink alcohol?

>>9570947
More often than not and even that doesn't make the pain go away.

I finally did it. I quit. I'm just not cut out for academia. I expected this to feel... to feel like anything really. But I can't feel anything at all. I'm neither happy, nor sad. Neither content, nor disappointed. It's like I died inside.

Any French faggots here? I want to go out for a drink now but I have no one to go with.

>>9570977
>>>/r9k/

>>9570977
my cousins boyfriend is french but they live in london

>>9570977
You have to live around Bordeaux btw.

>>9570979
Ok, I'll ask the robots as well.

>>9570900
i have a feeling half of the people on this general are larping as physics/cs-hating mathematicians but have not touched anything math since middle school other than copy-pasting wikipedia

>>9570900
>a mathematician not knowing
Reread my post more carefully. I said there is no reason for a mathematician to know that, which is true.

>>9571053
I'd claim it's something every mathematician has to know, but I'm willing to hear you out. Please elaborate.

>>9571059
There is nothing to elaborate on. It's clear that not every mathematician also studies engineering. So there is no need for a mathematician to know facts from engineering.

>>9570577
>why are the fundamental building blocks of societies allowed to do math?
You really have to ask this? On the women's day in particular? Talk about incel MGTOW.

How do I divide in Gaussian integers

How do I find GCD too?

Also how do I do the two above for Eisenstein

Please help

>>9571094
>How do I divide in Gaussian integers
a/b = ab^{-1}

>How do I find GCD too?
https://en.wikipedia.org/wiki/Gaussian_integer#Greatest_common_divisor

>>9570621
[math]\alpha[/math] was not assumed to be real
>yfw

any recommended books for learning linear algebra?

I'm a medical student (i am maths competent don't worry) that is interested in/doing research into neural networks and I would like to learn more about linear algebra

thanks

>>9571106
Fake

>>9571001
come to qc, french friend

>>9571363
>qc
quasi-compact?

>>9564732
because differentiation has easy stuff like the product rule

whilst integration has shit like integration by parts that is a pain to remember

>>9571072
Die whore

>>9571455
>>>/r9k/

>>9571458
Nice white knighting - too bad she won't let you fuck her for that

>>9564451
which one?

>>9571465
>Nice white knighting - too bad she won't let you fuck her for that
I don't "fuck" women.

>>9571468
I can believe that, beta orbiter

>>9571468
cringe.

>>9571472
>I can believe that, beta orbiter
I'm a straight woman.

>>9571495
Yeah, we all are.

>>9571495
You are an obnoxious tranny at best

>>9571465
>she

>>9571503
I have been encountered her on discord and I can tell you she's toxic

the rules are simple: if you're a tranny, post legs.if you're a vagina, post tits.

>>9571507
>I have been encountered her on discord and I can tell you she's toxic
No you have not.

>>9571515
420moonrunes666

>>9571255
aluffi algebra chapter 0

>>9571540
>aluffi algebra
should i go through the entire book or only the section on linear algebra?

>>9571547
I wouldnt suggest it unless you have a pretty good handle on basic category theory and ring theory

>>9571507
>discord
you have to go back

>>9570847
then you must be an intuitionist?

>>9571455
>>9571465
>>9571468
>>9571472
>>9571488
>>9571495
>>9571497
>>9571500
>>9571503
>>9571507
holy fuck shut up

>>9571671
Do you need to swear?

>>9571672
why the swearophobia?

>>9569999
yeah cuz everyone reads munkres in their first year, as evidence by no standard curriculum consisting of this

>tfw come back from college and see the shitstorm my 7 word shitpost started

What do people with degrees in pure Maths end up doing?

>>9572068
suicide

>>9572081
Does that mean I have only a few more years to live when I finish my degree

>>9572068
Meths

>>9571455
Don't talk to me, frogboy.

>>9572218
Go back to tumblr

>>9571570
You shouldn't be studying linear algebra if you don't have a good handle on those things.

>>9571853
>>9572094
>>>/r/eddit/

>>9572314
That's why I didnt suggest >he look at the LA chapter without those first???

>>9567542
Not exactly for that, but:
Sum (as n -> inf) from i=0 through i - > inf of f(a+i(b-a)/n)

>>9572335
dont be a fag