/sci/ - Science & Math

>>12243381 has a better op

>>12243390
It does not, it lacks soul

>>12243397
>hurr durr poincare disc tilings have soul
I remember when I was 13, dude. I couldn't tell what did and didn't have soul back then either. Don't worry, you'll grow out of it.

>>12243422
People lose soul when they grow up, it's common for adults to be nostalgic on their childhood and miss the "magic" of it. The soul of this image is that the groups of 3, and the deep blue color. It is reminiscent of higher lifeforms. I started my search for this image by looking at septagon tilings, which can be imagined as lifeforms like humans but with extra arm-limbs, or as centaurs if you please. It is like this song:

https://www.youtube.com/watch?v=twH8Y4iLLWI

>>12243380
How is twistor theory applied to nonlinear pde?

>>12243426
GBS is better.

https://4chan-science.fandom.com/wiki/Math_Textbook_Recommendations

All the Math You'll Ever Need: A Self-Teaching Guide by Slavin (All the *Arithmetic* you'll ever need)
Speed Mathematics Simplified (Dover Books) by Edward Stoddard
Secrets of Mental Math: The Mathemagician's Guide to Lightning Calculation and Amazing Math Tricks by Benjamin
The Mental Calculator's Handbook by Fountain and Koningsveld (More depth than the above, basic to intermediate level)
Dead Reckoning: Calculating Without Instruments by Doerfler (Warning: More advanced than the above, covers logarithms and trigonometric functions and their inverses, may require some calculus knowledge for maximum enjoyment)

Anyone tried to learn mental math? I want to do it but every book talks about different paths so i don't know which to choose.

>>12243438
isn't the only 'mental' math that you need to memorize a 10x10 multiplication table and the unit circle trig values?

>>12243442
I have 12 cakes and 93 people rsvp'd to my party! How much cake does each guest get... Will I have enough? And oh no!! The smog from the local power plant covered up the sun... Now my solar calculator doesn't work... Whatever will I do?

>>12243438
All the paths work. Simply learn the operations and practice on every day thing. Count things and measure volumes/area intuitively often too to get a good numeracy sense.

>>12243427
Any sort of nonlinear system with rotation, perhaps. And maybe to add extra dimensions to be able to simplify some terms

>>12243451
use pencil and paper?

>>12243461
Pencil and paper are arduous in my opinion, if you can eliminate the need you are freer. But I suppose you can

Are formal logic classes really that hard?

>>12242296
>>12242290
Terrible opinions

>>12243380
Looks like Morbid Angel album cover.
Anyways after reading Kant's Critique of Pure Reason I was thinking is all math just really how reality (time and space) is seen by human species and it solely depends on our perception?

>>12243618

>>12243646
Math is Inherently Metal

>>12243660
Absolutely.

What /mu/ does /mg/ listen to?
I've been listening to ttng

>>12243792
Great Big Sea, Slade, Adam and the Ant, some of Sting's stuff.

>>12243792
Chopin's nocturnes

>>12243792

>>12243798
Good taste

>>12243380
Bros pls help with proof, got no answers in /sqt/.
Prove that if [math]S \subseteq \mathbb{R}^n[/math] and [math]\mathcal{M} \subseteq S[/math] is the set of all isolated points of [math]S[/math] then [math]\mathbb{M}[/math] is countable

>>12243860
Shit, final M is [math]\mathcal{M}[/math] NOT [math]\mathbb{M}[/math]

>>12243826
This cover art is some serious uncanny valley.

>>12243860
>>12243864
Think about isolated points in general

>>12243792
Truly a wide variety

>>12243618
what the fuck no actual answer

>>12243882
What are you getting at?
A point [math]s \in S[/math] is isolated if for some [math]\epsilon > 0[/math] then [math]\mathcal{B}(s , \epsilon) \cap \{s\} = \emptyset[/math]
What else is there to consider?

>>12243928
That shouldn't be the empty set, it should be {s} on the right side of the equation. Anyway just remember that an isolated point is one whose Singleton is closed in the subspace topology, and R^n has a countable bases so the sub space should too, in other words your isolated points are countable.

So I lost my virginity tonight, and it didn't feel nearly as good as solving a good math problem. I think I may be autistic or asexual.

>>12243928
>>12243960
>That shouldn't be an empty set
You're right, I wrote the wrong relation, shit it's late. Should've been a set minus

>>12243960
I meant to say an isolated point is one whose Singleton is open anyway the rest of the logic still makes sense

>>12243960
Btw this is for an analysis class, not a topology class, I still haven't studied subspace topologies

>>12244006
Oh then I have no idea how you would prove this

>>12243961
How did it happen anon?

>>12243422
Man you're you're such a bitter red ditor.

Is linear algebra always taught in such a boring, non geometric manner or is it just my school?
99% of the work in my class is more suited for a computer than a human

>>12244058
The point of algebra is to embrace the geometry of the operators themselves, the geometry of inside and outside, the geometry of repetition, the geometry of inversion... Of paper markings. And they do correspond to visualizations of N dimensional euclidean spaces too.

>>12243961
Measure theory > sex > number theory

>>12244058
read Dan Pedoe's introductory geometry textbook, read a book on elementary differential geometry
>>12244086
>deleuzian-algebraist continental faggot pseudery
kill yourself brainlet

>>12244006
What if you bijected the integers with a discrete function

>>12244058
It depends. I was fortunate enough that my school offered linear algebra for mathematicians and linear algebra for engineers/computer scientists. The former was obviously proof based whereas the latter was computational based. From my understanding, this isn't uncommon, but also not the standard. I've never really understood why, though. In my opinion, linear algebra is the one math class that everyone should take from an abstract/proof perspective because once you understand it from that angle, everything else just falls into place. A regular computational based course is going to seem like a lot of arbitrary and unmotivated manipulations going on.

>>12243792
debussy, chopin, bach, a little vivaldi
>>12243804
based

>>12243792
https://www.youtube.com/watch?v=p5v-ytQ9GaQ
https://www.youtube.com/watch?v=sWtSmiaRdqg
https://www.youtube.com/watch?v=rFjcYwU69r8
These are my songs of tonight

>>12244006
each ball around an isolated point contains a rational point, think about that

Not yet bothered to study PDEs but I'm interested in physics so I think it should be useful. What's the rundown on the situation about them, I hear they're supposed to be really difficult in general, why is that? Also, where does one go to begin studying them, just learning various unrelated solving methods? Finally, do you guys think that medieval mathematicians would have had any edge in working with diff eqs due to working with polynomials so much?

>>12244104
Favorite one?
https://www.youtube.com/watch?v=t-JD2bnNQvY

>>12244104
faggot

>>12244126
The short answer is that the domain of a function for a PDE has a lot of flexibility and freedom and can admit a lot of different parameters. The overwhelming majority of PDEs don't have analytical solutions (this is also true of ODEs).

>>12244058
>99% of the work in my class is more suited for a computer than a human
What do you mean by this?

>>12244145
Any interesting, long videos to lull to sleep with?

>>12244154
I mean that my class is full of bothersome computations. Things a computer is meant to do.

>>12244162
This guy has a 12 video playlist on introductory PDEs and it's pretty good.
https://www.youtube.com/channel/UC3irR17bDfhuMlv0E4gwc_Q

>>12244165
... it is beneath the dignity of excellent men to waste their time in calculation when any peasant could do the work just as accurately with the aid of a machine.
—Gottfried Leibniz[

>>12244165
Eat your oats and do your pushups. How do you think the mathematicians before calculators got so smart?

>>12244174
Thanks mate and gut nacht

>>12244181
high iq
>>12244177
midwit

>>12244189
Night, lad.

>>12244132
Liking classical music is only faggoty if it's unprompted or they think it makes them better

>>12244295
I called him a faggot for his taste and diction, not for liking classical (based and redpilled, european, aryan, clean, spirited)

>>12244303
>diction
The only thing he said that weren't proper nouns were a little and based

>>12244303
Chopin is inarguably high IQ.

>>12244353
>he can't deduce the intellect of his peers from a single utterance
NGMI DESU
>>12244382
WRONG!

If you had said Liszt then you would be RIGHT, but you are not hi iq

>>12244392
Post one (1) Liszt piece that even comes close to this.
https://www.youtube.com/watch?v=YJMIIxm1bGo

>>12244110
I think it's this

>>12244110
Yeah I think I get it.
The 2 facts that matter here are:
1) that [math]Q^n[/math] is dense in [math]R^n[/math]
2) the fact that if you choose small enough [math]\epsilon[/math] then all intersections of neighborhoods around isolated points are empty
Now we se that to each neighborhood of an isolated point I can associate 1 rational number because of (1) and we know than no other neighborhood will have that same rational number because of (2) thus we have a mapping [math]S \rightarrow Q^n[/math] that constitutes an injection and so the isolated points are at most a countable set.
Please correct if any part of my reasoning is flawed

>>12243422
Hyperbolic tilings are maths, unlike logic.

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

The occasional but notable tie between math fags and either chess or classical music (or both) is fucking annoying.
Ironically I don't have too much against the math+anime association on sci

>>12244962
anime is peadophilic

What's the main difference between doing a post grad qualification in math on the more applied side of the spectrum, and theoretical physics?

I love math and I love the theory behind physics, but I hate the lab work (I like doing the experiments but I just hate the write ups or even reading others studies). So I figure theoretical physics is more my thing, but I don't really know how to pick between it and math.

>>12244962
Why? Does it make you feel inadequate?

>>12244047
hooked up with a big titty goth girl from tinder. We makeout, gives me a bj, and rides me. Overall pretty lame,i was ready to kick her out and get back to my maths. Sound like I larp I know but sex really is overrated.

Greetings, /mg/. Is anybody here familiar with differential algebra, in particular differential ideals? I've skimmed through the famous book by Ritt, and apparently they haven't even solved the membership problem by then.

My question is: why does it seem like nobody cares about principal differential ideals? Are they poorly defined? It is difficult to find anything about them. I have a sketch of a naïve proposition about them, which arose from my field of studies, but the absense of similar results worries me.

>>12244087
So if my field mixes number theory and measure theory, is it just exactly like having sex?

>>12244962
>mathematician character introduced
>starts rambling about the language of god

>>12244962
Agreed, all math people should be social outcasts and have mostly low-class hobbies such as anime and video games

>>12243422
Embarassing.

I just don't have the intuition for factoring.
Can anyone direct me to some intuitive method of understanding why:

ax^2+bx+c = a(x^2+b/a)+c

>>12243961
Sex is temporary. Math is eternal.

>>12244461
Precisely. Incidentally, this is why you can only fit countably many disjoint open sets in R^n. Keep this sort of density argument in mind, comes up sometimes later in topology when you need to prove things about separable spaces.

>>12245290
I guess I've learned a small amount of differential algebra but I cannot possibly answer any questions about it. Sorry.

>>12244962
What's wrong with chess or classical music?

>>12245433
Well there's no intuition because it's not that. You lost an x.
ax^2 + bx + c = a(x^2 + b/a x) + c
Your intuition from this could come from multiplying a back in, what happens when you do that? The x^2 gets an a, and the b/a is multiplied by a, which just gives you b.

>>12245433
ax^2+bx+c doesn't equal a(x^2+b/a)+c, though, it equals a(x^2+bx/a)+c

>>12245433
Break ax^2+bx+c into (ax^2+bx)+c

>>12245488
I explicitly say it's the bunching together of the things. It's like you go to a programming course and 16 of the 20 people in class constantly spam irrelevant shit about yu-gi-oh trading cards. Worse, the chess and classical music fags even think it makes them a smarter company for it

>>12245480
Awesome dude, thanks!

>>12245491
Omg, thank you, I was having an aneurysm trying to understand the b/a, maybe because I was looking at it in fraction notation.
>>12245493
Oh sorry, I just typo'd.
I was looking at the correct equations in demos, so i know i had them right, i just typed them wrong here.
>>12245498
Ty

>>12245607
>Omg
>Oh sorry
>typo'd
>Ty
>i just
>having an aneurysm
>>>r/mathhelp

>>12245625
Someday you will understand how embarrassing your attempts to embarrass others are.
Well, if you're lucky.

>>12245527
>Worse, the chess and classical music fags even think it makes them a smarter company for it
Are they wrong?

>>12245277
I know that feel brother. I lost mine to a Jewish girl with big milkers over a year ago. I fell for the Khazar milkers meme. I’ll never cheat on maths again.

>haven't lost my virginity so I can still use magic to materialize proofs
How can non-virgins even compete?

>>12244888
>P. P. Weiner raised an example of a large scale application of Leibniz's characteristica to climatic science. A weather-forecaster invented by Athanasius Kircher "interested Leibniz in connection with his own attempts to invent a universal language" (1940).
>P. P. Weiner

>>12245607
die low iq nigger

>>12245290
Whether you're a student or faculty just ask some people in your department, try to prove some things you have in mind and maybe it'll be a topic you can research

In this picture, the middle three polygons are concave but they can be divided. The middle polygon of the three does not contain a point from which rays can be drawn to touch any part of the polygon without leaving it, but the other two do.
Besides just saying lol they're all concave why does it matter is there a term for the property I'm trying to describe?

>>12245973
If you number them left to right as 1,2,3,4,5 you could say that for polygons 2 and 4 there exists at least one point within them from which they "appear" convex, even though they aren't.

>>12245973
ability to give a fan triangulation

can a magma be associative, or would that make it a semigroup?

>>12245990
Fan triangulations start from a vertex. Is it provable that if a subset of points in a concave polygon has the property that at least one vertex is within the subset?
No, because a really narrow pentagram is an obvious counterexample.

>>12245990
Not all star domains are fan triangulable.
>>12245973
https://en.wikipedia.org/wiki/Star-shaped_polygon

>>12244962
>>12245527
i think there's a significant amount of people in maths that just like to think about themselves as "intellectuals"
and more often than not, i find them obnoxious

>>12245998
in other words, is a semigroup a magma?

>>12245998
By definition a semigroup is an associative magma.

>>12246069
okay, so to prove something is a magma, all i need to show is it's associative?

im asked whether something is a magma but it is also associative, so it is still a magma right?

>>12246099
i mean all i need to show is it's closed to show it's a magma, even though it's also associative

>>12246099
Yes it's still a magma Jesus Christ

>>12246156
im sorry english isnt my first language lol

>>12246161
What is your first language?

>>12246208
finnish

>>12246217
Huh, me too

>>12246217
>>12246239
Meil samat.

>>12246217
>>12246239
>>12246243
Tuu tappelee

>>12246248
Ookkonää Oulussa?

>>12246256
>Oulu

>>12246217
Based.

>>12246277
Ortotopologian huippututkimuskeskus!

>>12246312
based and orthotopology pilled

Threadly reminder to give your credit card information to physicists

>>12246433
I don't like physics or physicists.

>>12243380
Attention graph of robot shouldn't be flattened, we have infinite proportional or dimensional or how does it space by relating all relatants in graph or by coupling two ids in database, we don't have to live on flat space on robot.

But it's look like attention span, that can move only in in white bound, minimizing energy is around, and then you as you travel to the edge something gets bigger, because there's this hyperbolic space.

>>12246451
Can you explain this more precisely please?

>>12246635
I imagined this is what from robot's computational abilities is currently computed, the attention span, with clusters being focused, which all have relations but focus can travel only in white rectangle separated clusters, as it moves to the side, ( side object is centered ) it gets bigger and centered object moved to the side smaller. Area is allocated computing capacity per subject.

But I mean, they don't have to be on 2D space, but they can be interconnected graph nodes, so there would be more roads trough something like hyperspace we could travel in.

>>12246672
Ah I see. I don't see why they couldn't use the hexagons though, to interact with multiple thoughts at once. In fact I think neurons do that, you can fire one which perturbs multiple in a grouping

I groomed my little cousin into becoming a femboy and a mathematician

>>12246870
Nice. Are you going to share him with the rest of your bros?

Why is computer algebra so unpopular in the states? It seems like a really based field.

>>12247117
It's because Americans have brain damage
t. American

The solid of intersection for two cylinders at right angles is the steinmetz solid, which is the same as taking an axis-aligned unit cube centered on the origin in 3d space and transforming the radius at each y to r(cosy).
If the original cube has volume 2, does the steinmetz solid have volume 4/3 like a sphere in a cylinder?

>>12247148
I would assume it applied for all solids of that nature relative to their original prism, regardless of how many edges they have.
The formula for the volume of an m-sided pyramid is the same for all m, after all.

>>12247148
So this solid is made from attaching 4 90° wedge cylinder intersections around a square, one for each side.
If we extend the cylinder to permit any kind of elliptical prism with minor axis equal to a cylinder radius, can you make such a solid for any convex polygon?

Diese Welt ist sehr sehr furchtbar!
Und ich hasse es alles!
Ich hasse es alles!

Meine Lungen sind mit Asphalt gefullt
Und meine Hande zu blod fur arbeiten
Meine Zahne sind zu schwach, zu schwach zu reissen
Und meine Haut ist zu kalt, zu kalt zum atmen

Aber...
Ich habe..
Eine schone
Und heilig Keine

>>12247349
Speaking in non-English languages outside of /int/ is a bannable offense.

Goodnight math general. Please remember that God did not want us to waste our lives in fluorescent lightbulb caves, obsessively wrestling with algebraic demons from unknown dimensions, but to meditate under Heilig's eternity and map the patterns that govern reality. Those algebraic demons, too, may be seen by future minds who live in that realm. But we live where fractal trees and non euclidean orbits roam, so let us see those! I think the anon who suggested Navier Stokes as a worthwhile endeavor was true.

Maybe tonight I may read and write again after a week of nocturnal napping... maybe...

>>12247362
I am not afraid of getting banned! I don't think bureaucracy is necessary in the living room.

>>12247367
Night, lad.

>>12246870
How old is he and do you incest

this is dumb as fuck but I gotta ask this
Is there a difference between how you compute a Riemann Integral and a lebesgue integral or is is the same 'take the antidirevative and do the thing' for both?

>>12243792
Lots of metal, mostly thrash although lately black, some rock, some indie. Anything with a guitar suits me.

>>12244962
Why would anyone play chess instead of go

>>12247633
Thrash is inherently high IQ.

i'm not going to make it bros...

Just realized my grant proposal is dogshit

finna take the smith and wesson retirement plan

>>12247511
well that works, but if you don't know an antiderivative then to compute a riemann integral you take partitions and then limit, and to compute a lebesgue integral you approximate by simple functions and then limit.
this is almost always identical unless you have conditional convergence issues (sin(x)/x) or your function isn't riemann integrable.

>>12247917
Is it because the thing you're researching is dog shit or is it just that you think you could have done better?
Either way I believe in you

It's not different in most cases you'll come across that you actually want to compute, because in fact the Lebesgue integral is equal to the Reimann integral when the latter is well defined. When the function is not Reimann integrable you have to do some magic by partitioning up the range and whatnot, or else numerical methods. Someone that actually knows what they're talking about can probably give a better answer.

I also have a dumb question regarding integration. If we have [math]\lim_{M\rightarrow\infty}\int_{\Omega}X \textbf{1}_{X\in[-M,M]}d\mathbb{P}= a[/math], can we conclude that [math]\left|\mathbb{E}[X]\right|<\infty[/math]? It seems intuitive but I don't see how it would follow directly from bounded/monotone/dominated convergence.

>>12248010
sorry, where [math]a\in\mathbb{R}[/math]

>>12248010
baka also this was meant for >>12247511

>>12247511
>or is is the same 'take the antidirevative and do the thing' for both?
So do you even know how to compute a Riemann integral directly using the definition?

>>12248233
I just do what I'm told otherwise professor will take a wrench to my face again

>>12248239
Can you answer the question? How do you compute a Riemann integral of a function with no primitive?

>>12247917
bro...
don't you have an advisor that would help you out?
my grant proposals were filled by my advisor and i've barely even read the shit he wrote

>>12248247
Not him but this a natural line of questioning imo. At least when I first learned about lebesgue integration I was curious if there was some sort of analogue to FTC with primitives procedure that you first learn.

>>12248378
Sure, but the way he phrased it made it sound like he doesn't know how to directly compute Riemann integrals.

>every fucking faggot I talk to says "just have your advisor write it bro"
>after I already submitted multiple grant proposals about a subject I'm barely familiar with
>advisor says "yea I could have written something but I thought you wanted to practice"
end me bros

>>12248421
bro...
i wanna end myself too...

>>12243792
Vocal jazz for the most part

Thoughts? Changes? Additions? Accuracies/inaccuracies?
This is all just going on the people I've interacted with online/in person in all of these areas.

>>12244126
Look up Carl Benders book, its god tier

Why do real numbers have the least upper bound property? If a subset is closed, makes sense. If a subset is open, is it because in order to be open it has to be defined in relation to some upper bound?

>>12248912
This one?:

https://www.thriftbooks.com/w/advanced-mathematical-methods-for-scientists-and-engineers-i-asymptotic-methods-and-perturbation-theory/9081422/item/5367858/?mkwid=%7cdc&pcrid=448963509244&pkw=&pmt=&slid=&plc=&pgrid=104673973815&ptaid=pla-926982115650&gclid=Cj0KCQjw8rT8BRCbARIsALWiOvRbRHYDiIDeOWx1DlxOFe2QNao3tYa-8-uOyqj51psR2TOLilVGj_EaAoJIEALw_wcB#idiq=5367858&edition=5214176

>>12248916
>is it because in order to be open it has to be defined in relation to some upper bound?
That's a really good way of thinking about it. Of course, the proof is a little bit more work using various possible definitions of real numbers.

>>12248847
Diff geo is comfy here, mathematical physics doesn't make sense, logic is spot on, and combinatorics should be an autistichad

>>12248922
yeah

>>12248847
holy based
probably swap category theory and graph theory

>>12248847
>category theory
>no tranny

>>12248916
kind of just an obvious consequence of the definition by dedekind cuts, just union all the cuts in a set
if instead you define the reals to be the completion of the rationals, pick upper bounds which are within 1/n of some element in your set (now why can you do this?) and form a cauchy sequence

>>12249082
>now why can you do this?
Because it has an upper bound and the reals have the archimedean property.
Start with the upper bound and keep going down by 1/n distance, and stop when your next step will no longer be an upper bound. You will always stop somewhere by the archimedean property.

>get a 40/100 on my first linear algebra midterm
>have to drop the course now

why am i so stupid i'm shakign and criyjng bros

>>12248847
why applied math is so bad?

>>12248847
Made chuckle thanks anon

t. analysis chad

>>12249109
Sorry anon, do you need the class to graduate? Linear algebra is often an engineering plug and chug course and worth skipping if possible and self-studying the material.

>>12249159
Applied math is the chad option. Imagine spending half your life and all the mental energy of your youth working on a shoestring salary to prove to some crusty old men that you're worthy of joining their intellectual guild. All just earn the right to be paid half of what someone 20 years younger than you is making. But hey, at least you get to spend the rest of your life circlejerking with the 5 people on earth who actually care about what you do.

>>12249191
I do need it to graduate, I'm hoping I can self-study to prepare and try again in another semester. The only upside is that it's not a prerequisite course for anything else so it's not going to cripple my advancement through the program.

>>12248847
Don't get Math Phys

Hope this is the right place to ask...

I'm a mathlet that would like to get up to speed on probability from a practical/non-rigorous approach. I've determined that I'm going to need at least some cursory knowledge on the subject for a programming project I'll be working on in the near future. What are the perquisites for studying this stuff? I'd appreciate any resources and recommendations.

Thanks in advance.

>>12249247
Think about all situations vs the occurence of a certain situation within that, find the ratio

>>12248916
Real numbers are essentially characterized by the least upper bound property.
You cannot find a proof of this that is not tautological to some extent.

>>12249247
If you can make it through Sheldon Ross's "A First Course in Probability" and "Introduction to Probability Models" (i.e.: you can do all of the exercises), then you should be very well-prepared for your purposes.

>>12249092
Precisely. Hope you were the guy who asked the question though, lol. The question was meant for him.

>>12249109
git gud, put your head in the books and try again

and then if you fail the next time then consider a career change, maths isn't worth you stressing over and it's certainly not worth it in the long run

Test

>>12249262
I attempt to find a way to describe a set of reals such that the least upper bound property does not hold, but I can find no such way.

i like math

>>12249359
based

>>12243792
I like classical music, specially Schumann, Brahms and Ravel. But lately I've been listening to Autechre's new album and Coltrane

>>12243961
Nothing gives me better orgasms than reading mathematical objects with scary names. I had attacks of autism when I first read about "strongly zerodimensional spaces"

>>12244058
As a pregrad studdent I can confirm. The thing about linear algebra is that it is one of this branches with "lots of applications", therefore it is often taught with that approach. Like calculus.

>>12244104
Let me guess, you like Debussy's Clair de Lune and Preludes, Chopin's Nocturnes and Waltes, and Bach's Cello Suites and Fugues, am I right?

>>12244165
I know the feel too, and I hate it. There is no point in doing complex calculations by hand given that a computer can do them in half a second

>>12244382
Everyone has heard a Chopin piece, and no, you are not smurt for knowing his Nocturne op. 9 no. 2, that just shows you listen classical music in a superficial way

>>12244962
I don't see any problem in liking maths, classical music and chess. If you like mathematics why is it a problem for you to like one genre of music rather than another, or to play a game instead of that other game. I think you're just projecting, anon

>>12248847
>Analysis smurt
engineers are not smarter, anon

>>12244962
It makes sense. A lot of people that study math at a high level were overachievers growing up or had parents that pushed them a lot. Learning a classical instrument / chess is a byproduct of this.

>>12248847
Operations Research is NOT a field of mathematics

>>12249368
holy fuck, fucking moron replying to everyone. and no, i hate clair de lune, its a piece of shit. i like la mer and the images suite.
for bach i mostly enjoy his concertos.
for chopin, i do like his nocturnes and waltzes. specifically, i like op. 27 no. 2 the most, and the op. 55s. op. 9 no. 2 is boring like clair de lune.

>>12249371
>my analysis experience is limited to introductory real analysis with baby rudin and an undergrad pde course: the post
holy cringe

>>12244104
Don't forget Listz and Raminoff.

I unironically really enjoy mathologer videos

>>12244423
https://www.youtube.com/channel/UC3irR17bDfhuMlv0E4gwc_Q

>>12249649
What do you ironically really enjoy?

>>12249672
Resident Evil movies

>>12249386
>not studying math after a teenage career as a druggie burnout

Ngmi

>>12248847
seems like an entirely arbitrary assignment

>>12249386
overachievers do shit because they are told what to do and enjoy, thats why you see a lot of pseuds who force themselves into “that” kind of stuff. while doing that by itself doesnt mean you are that person, it is a strong indicator.

>>12249749
Yes, and?

>>12249209
Imagine thinking anybody cares what you do regardless of what it is. Imagine thinking money is the answer to all your problems. Imagine thinking applied math is better than pure math.

>>12249803
>money is the answer to all your problems
>applied math is better than pure math.

>>12249109
Same. I actually thought I was doing fantastic, I even helped my classmates a lot.
My country is garbage though so they will let me take the exam again.

>>12249880
Romania isn't that bad.

>>12249209
One of the hottest mathematicians I have met is a combinatorist with the body of a rugby player. Combinatorics is the chad option.

Choose one and ONLY one:
>'spee-væk
>'spee-vek
>'spee-vukh
>'spih-væk
>'spih-vek
>'spih-vukh
>'spy-væk
>'spy-vek
>'spy-vukh
>'spuh-væk
>'spuh-vek
>'spuh-vukh

>spee'væk
>spee'vek
>spee'vukh
>spih'væk
>spih'vek
>spih'vukh
>spy'væk
>spy'vek
>spy'vukh
>spuh'væk
>spuh'vek
>spuh'vukh

>>12250051
>not using ipa
Fuck off this is meaningless

>>12250051
rudin

>>12250057
I was making it understandable to the anons who are unfamiliar with IPA. Being accommodating to others will get you far in life, faggot.

>>12250063
This.

So I know that if you have
P iff Q
You can substitute P for Q in zero order logic but what would be the name of the deduction rule that this uses.
Would it be a hypothetical syllogism

>>12250063
>>12250066
I obviously reference him in relation to his differential geometry books.

>>12250066
>>12250063
Ridiculous

>>12250065
Be accommodating, not a doormat.

>>12250101
No

>>12250114
¿Are you insisting on being a doormat, contrary to my wishes?

>>12248847
mathematical physics gang checking in

>>12243792
Molchat Doma, King Gizz, Adolescents, Dead Kennedys, Kino

hey guys, I'm sorry to bother you with what's probably basic algebra homework, but I've been stuck on this problem for an hour now and I can't figure out which x in S_3 is going to give a different result if I express it differently inside f( )
(I'm talking about question 5c)
Can anybody point me in the right direction?

[eqn] x_0(t) = sin(t)
\\
y_0(t) = cos(t)
\\
x_{n+1}(t) = x_n(t) +(sin(n x_n(t)) +sin(n y_n(t))) /(4n)
\\
y_{n+1}(t) = y_n(t) +(cos(n x_n(t)) +cos(n y_n(t))) /(4n)[/eqn]

I believe the limit as n -> infinity is a jordan curve that is nowhere differentiable. I wonder, what is its hausdorff dimension? What kinds of approximate self-similarity properties does it have? Can every jordan arc be approximated arbitrarily well (in hausdorff distance, say) by scaled up copies of small parts of this curve? If not, can you construct a natural curve that does have this property? (It is easy to construct one with artificial, piecewise constructions)

[math](x+1)|(x^n+1)[/math] iff n is odd.

I remember this formula from some class years ago but have no idea what its called or how to prove it. Anyone know?

>>12250690
Symmetic group on 3 elements isnt that big
try them all

>>12250750
add zero in a clever way

what does /mg/ drink to dull the pain?
for me, it's gin or rum

>>12250767
Blood

>>12250767
Undergraduate blood.

>>12250767
Freshmen's dream.

>>12250793
>>12250824
ah, so you too are alcoholics.

>>12250767
Apple juice ^o^

doing a lot of dynamical systems / mathematical physics type stuff I hear a lot about

>hyperbolic sine, cosine
>Bessel functions
>elliptic integrals of the nth kind
>Gamma, beta functions
>Lambert's W function

Generally speaking, I'm only ever required to compute with these functions as certain properties relate to them, but to leave numerically evaluating them (as real numbers or as complex numbers) to a computer somewhere.

If I actually wanted to understand what these functions represent, why they're not expressible in terms of elementary functions, and how I might go about writing algorithms to approximate them anyway, do you guys have any recommended reading?

stupid question but im doubting myself

If [math]\phi_i:M\to N_i[/math] are maps of modules, is it true that [math]\ker\left(\bigoplus_i \phi_i\right) = \bigoplus_i \ker( \phi_i)[/math]?

I'm trying to show that cohomology commutes over direct sums and it would follow from this

losing my mind friends, Evans seems to introduce a new piece of notation every other line. Then again this is my first time studying PDE so maybe this is all standard stuff.

>>12251090
If it's your first time studying a subject, why did you get a grad level text?

>>12243792
Vaporwave and rap

>>12245625
Kek

>>12245681
>Someday you will understand how embarrassing your attempts to embarrass others are.
I don't think they need that anon to embarrass themselves

>>12248847
>applied math
Wrong

>>12249803
>le math monk meme
Piss off undergrad

>>12250767
Rolling rock

>>12249803
imagine spending your time caring about what others study.

>>12251160
>meme

>>12248847
Fuck this is actually pretty good

Every time I ask a pure mathematician to define what applied mathematics is, they shrug their shoulders in indifference, where can I study this stuff at the graduate level?

>>12251373
your local council's garbage disposal facilities is a good starting place, if you can't find any applied mathematicians there then try mcdonald's or wendy's

>>12251380
You're mistaking applied mathematicians with pure mathematicians.

What math should I study to become smart like you guys??

Why is probability so fucking hard? I barely passed an undergraduate level probability course but do just fine in graduate level numerical analysis or Fourier analysis courses. Probability problems for me seem like they pull properties of the problem out of thin air that do not seem intuitive to me. Anyone else feel this way?

>>12251429
>>12249278 here, it only feels unintuitive to you because you lack practice.
I recommended Ross precisely because his books are abundant in problems, both theoretical (prove T) and applied (use your knowledge of T to model P).
I'd advise similarly to you: reviewing the problems in Ross, and checking that you understand how to solve them (which shouldn't be hard if you're already familiar with the material), will go a long way towards dispelling your worries about lacking intuition.

If Ross is too nontheoretical for the sort of problems you're working on, you could try pic related as an alternative.

>>12251181
Wanting your work to have real applications and reach a wider audience with the added benefit of a potentially higher salary is nothing to scorn someone over famalam.

All math is applied math.
Pure math is just math applied to itself.

hi, I'm on the last problem of my algebra homework and I don't know what they mean when they say (H*x) is taken to the power n. The other side makes sense, but I wasn't aware a coset could be taken to a power.

>>12251738
The elements of a quotient group are technically the right cosets, in other words (H*x) is just like any other element and can be raised to a power

Moivre
Cauchy Reimann

>>12251380
Based retard.

>>12251881
Reminder that de Moivre's theorem shows up zero (0) places in his notes and or publications.

>>12251101
>>12251090
In this anon's defense, I was able to get through my first PDE course with this text. I feel like I'm pretty shit at PDEs but I got a lot from it for sure.
For your concerns, I don't know if you have a university course to go along with, but just supplement it with outside material. He does introduce things fast, so I don't really know if it is an ideal self-study book. Just ask stupid questions, think about them, if you can't get an answer, look them up. You'll be fine.
Some of the exercises in the book are hard as balls with no PDE background though, I will say from experience.

>>12251380
>We're reaching projection levels that shouldn't even be possible

>>12248010
no, picture X = 1_[0,inf] - 1_[-inf,0]
The limit you wrote is 0, but the function is not absolutely integrable/Lebesgue integrable. Therefore E(X) is not defined. You can only talk about it as a limit.

>>12243618
Yes, it is.

Hi /mg/!

>>12251015
Yes. You would have [math](m_i) \in \ker( \bigoplus_i \varphi_i) \Leftrightarrow (\varphi_i(m_i)) = (0, 0, \dots) \Leftrightarrow m_i \in \ker( \varphi_i)[/math] for each [math]i[/math].

>>12252047
Given any surjection [math]f\colon A\to B[/math] and any morphism [math]g\colon \text{>>12251380}\to B[/math], there exists a morphism [math]h\colon \text{>>12251380} \to A[/math] such that [math]f\circ h = g[/math].

>>12252259
Hmm it worked in the preview. I guess the underlying board code overrules the latexing.

>get baited into thinking about set theory once again
>think for an hour about axiom of regularity and equivalent formulations
FUCK
THIs
CANCER

>>12251169
Anon is probably a psychology or sociologist

>>12251738
>>12251816

You can also think of [math](H \star x)^n [/math] as the group of products of n elements of [math]H \star x[/math]

>>12243792
Magnetude, Ghost Data, Droflam and The Strokes.

>Bother to learn scheme language
>Finally become comfortable with the notations in the most general settings
>Finally confident to pick up textbook about diophantine geometry and get working
>They use the language of varieties
>Have to translate everything back to scheme language to be able to use my intuition

Does there exist a real algebraic number x < -1 such that both 1 and - 1/2 can be written as sums of distinct powers of x? If we drop the distinctness condition it's easy, take x to be the real root of 2x^3 +2x^2 +1 =0, then - 1/2 = x^2 +x^3 and 1 = 4x^6+8x^5+4x^4 . But the equation for 1 uses 4 copies of x^6.

>>12252287
But hey it's just a theory (a gauss)

>came up with stupid math idea
>what is the "instantaneous average" of a function
>formulate it as
[math]\frac{\int _{a-\delta }^af\left(x\right)dx\:}{-\delta }[/math]
>graph it
>realize I'm a moron and it's just another formulation of the derivative

>>12252532
Hmm, that doesn't seem right. It should converge to f(a) as delta goes to zero, as long as f is continuous. However, [math] \frac{12\int _{a-\delta }^a(x-(a-\frac{\delta} {2})f\left(x\right)dx\:}{\delta^3 }[/math] should converge to f'(a) as delta - > 0 as long as f is continuously differentiable.

>>12252594
I see that now. What I was thinking was, "We're integrating something but getting the original function out of it somehow" -> "Derivative" (fundamental theorem)

what I'm trying to do is find some way to plot a moving average but I must be a midwit because I keep on just getting the original function when plotting the integral. I'll figure something out.

>>12243792
Math rock ^^

>>12251962
Thanks! I'm actually just focusing on Sobolev spaces for the moment, and a professor I know recommended this text for reference. I'm planning going through the first part of the book in depth at some point so will keep this in mind.

>>12252687
Are you excited for tricots new album coming out tomorrow? What bands do you listen to?

>>12252059
Yes this makes sense. I was confused because a theorem I cam across seemed to conclude from this something like E(X)<\infty while E(X)=\infty, but I reread it and you're right, it was only being discussed in terms of the limit.

>>12252650
To get a moving average you need to leave delta large.

>>12252411
Where does the question come from? Seems very arbitrary.

>>12252775
Did not know that tricot had a new album coming out tomorrow thanks senpai
Mostly asian groups like Elephant Gym, Toe and Lite. Also Physics House Band is one of my favourite. Been listening to a lot of Poly-Math tho recently i recommend Ekerot and Babel if you feel like checking them out.

Why does the Organic Chem guy move ^1/7 and turn it into *1/7 . Those aren't the same I feel like I forgot some basic Algebra rule

>>12248847
I mean I'm OR and that is how I dress and feel inside so at least that parts right.

>>12252965
ln(x^a) = aln(x)

>>12253001
WTF why.
The only one I know is ln(x^a) = (x^a)'/x^a

>>12252775
https://www.youtube.com/watch?v=swXerd-HkVs
https://www.youtube.com/watch?v=gdYczmD9gC4

>>12253008
get familiar with those log properties because they come up a LOT in later math

Out of curiosity, is there a giant fucking book of Real Analysis problems I can keep working until I finally get the subject or should I consider suicide?

>>12253150
will do, thx

>>12253186
Any textbook? I mean Pugh has like 100 exercises at the end of each chapter so that'd probably be a good place start. If you're talking real analysis, Folland also has a shitton of exercises. If you want just hard problems that will make you really really understand analysis, consider "Problems and Theorems in Analysis I" by Polya and Szego.

>>12253008
Remember what [math]x = \log_a b[/math] actually is. It is the number [math]x[/math] such that [math]a^x = b[/math]. Now, [math]e^{\ln(x^a)} = x^a = (e^x)^a=(e^{\ln(x)})^a = e^{a\ln(x)}[/math]. If you then use the fact that the exponential function is injective, you will get that [math]\ln(x^a) = a\ln(x)[/math]. You can replace the base number with any positive real (and the logarith correspondingly) and it will still be true.

>>12253229
This works, thanks
imma give you a small kiss for your help

>>12253231
Forget that [math](e^x)^a[/math] in the middle, it's a total brainfart.

>>12253231
x^a = e^ax
How come?

>>12253283
>>12253281

>>12252943
I was thinking about negative and non-integer bases, and it occurred to me that if there was such an x every dyadic rational, positive or negative, should have a finite base-x expansion without a decimal point using only 0 and 1 as digits, which seems really neat.

Yesterday I discovered that all the parabolas of form y=x^2 + a partition the plane and don't intersect, by using equivalence classes. It felt surreal, how can such a nonmathematical way of working prove a concept based on slopes? Yet it works. Weird world.

>>12253357
Nevermind, I witness how the equivalence class method contains the slope searching method. But sometimes weird things do exist in math.

>>12253367
Wtf are you talking about with slopes.

>>12251169
Imagine applying mathematics.

>>12253426
An inefficient method and high coarseness

>>12253767
Thanks for today's dose of schizophrenia on /sci/.

>>12253231
fucking retard

>>12253803
chill guy he posted the correction

A circle is just an imaginary hyperbola... What the fuck is going on here?
>x^2+y^2=1
>y=sqrt(1-x^2)
>y=sqrt(-1(x^2-1))
vs
>x^2-y^2=1
>y=sqrt(x^2-1)

>>12253920
wait until you discover imaginary-side-length triangles bro...

>>12253934
Nontrivial circles of radius 0 is where it's at.

>>12253920
wait till you hear about projective planes

>>12253956
I have, I just don't understand them much at all. This hyperbola thing is so weird to me, I need insight

>>12253920
I did notice something maybe, if you plot imaginarily the part of a hyperbola that can't real, it becomes imaginary circle, and vice versa with circle

Can anyone help a retard out? I have this question on a small assignment and I'm not sure how to proceed.

True or false:
Consider a and b real numbers. Then, [a]=[b] if and only if |a−b|<1.

(Note, it is Floor(a)=Floor(b) iff Abs(a-b) < 1)

I was able to prove LHS => RHS, but I am not sure what to do with the converse. Clearly it doesn't always hold true, but would it suffice to show a counter example for the converse to disprove an iff statement?. There is no universal quantifier here and every single T/F question of this sort in the past has been true so I have no clue what to think of it.

>>12254024
>would it suffice to show a counterexample to disprove a statement
Yes

>>12254024
>There is no universal quantifier here
That's where you're wrong bud. It says for all a and b...

>>12243381
Neu

>>12254031
That abomination was competing with this /mg/ already. It's not new.

>>12254039
No point wasting an extant thread and letting a secondary drag on

I just had a horrible week and it just started so i need some help to cope with it. Can you give me the image of the dude that sorted the data before doing linear regresion? I want to have sum laugh

>>12254039
It's newer by one post.

>>12254039
Cope. Seethe. Discombombulate.

>>12254029
>>12254030
Ah ok. So the question is basically just stating that for any pair of real valued a and b, we have TT or FF when looking at the truth values of both sides of the iff statement (otherwise one implication would incorrect)? Therefore just showing that it doesn't work for let's say a = 3.2 and b = 2.7 would work as justification for False since both are real numbers and we have the converse being false due to T => F?

I'm sorry about polluting the thread with brainlet shit.

New thread
>>12243381

>>12254104
If you break one side of the iff, you break the whole iff-ness of it. If your statement is, "for all x this is true", then having one x be untrue means its not true for all x.

>>12254132
Thank you for the clarification, it cleared things up for the rest of the assignment, thankfully. The whole imp;lied quantifier thing confused me apparently and I was on the verge of tearing my hair out trying to prove false statements :/ ....

>>12254115
no
>>12254031
Speak english euro-fag