Mathematician Chat V.floor(π)

[Krinkels]

You're right! It's not valid to take the derivative of m.

The identity you should have remembered is:
sin^2(x) + cos^2(x) = 1

[JohnnyMo]

Ugh. Had an advanced calc test. He put all sorts of series of functions shit on it that we never had homework on. Only lectures. I didn't study most of it because I figured it wouldn't be on there if we haven't actually done it.

I really wish the university would just let me skip this class. I've already taken real analysis so it's a complete waste of my time.

[Dvd_]

[QUOTE=JohnnyMo1;43073111]Ugh. Had an advanced calc test. He put all sorts of series of functions shit on it that we never had homework on. Only lectures. I didn't study most of it because I figured it wouldn't be on there if we haven't actually done it.

I really wish the university would just let me skip this class. I've already taken real analysis so it's a complete waste of my time.[/QUOTE]
Is advanced calc the same as multivariate calculus?

[Mr. Bleak]

What school do you go to again, Johnny?

[JohnnyMo]

[QUOTE=Dvd;43073745]Is advanced calc the same as multivariate calculus?[/QUOTE]

No, it's proof-based single-variable calc. Basically a first analysis class.

[editline]4th December 2013[/editline]

[QUOTE=Mr. Bleak;43073831]What school do you go to again, Johnny?[/QUOTE]

Virginia Tech

[mastoner20]

[QUOTE=JohnnyMo1;43074293]

Virginia Tech[/QUOTE]

Woah, I'm only about 45 mins north of you in Roanoke...

[JohnnyMo]

fite me

[mastoner20]

I think I'll pass... I don't want to get bloody on the one and only day of the week I get to wear casual clothes... :(

[Falubii]

Facepunch Arena. Someone make it happen.

[Neckbird]

[QUOTE=Jellyman;39794673]I'm so envious of you guys.
I lack any sort of math education and Khan Academy is haaaard.

I can hardly simplify fractions.
And I can't do factorization.

:([/QUOTE]

I missed so much school from truancy and moving, that i didn't know what PEMDAS was until i was around 15. I was left back only one year somehow. At least I ended up giving grad speech, since my last two years in high school i really pushed myself.

Now that i'm in college, (going for engineering) it made me realize how i don't have nearly the same math intuition as my peers, and my math courses which are entirely new to me, are just re visitation for them. I saw this coming, and used Kahn Academy to prep myself, but that wont replace the years of practice in school which I missed out on.

BUT, now i'm starting to get higher grades than many of those peers, particularly when it involves more visualization than arithmetic. Make sure you know prerequisite knowledge, since math is learned cumulatively, and practice hard. You'll get there.

tl;dr - Start wherever you can now, and work from there; or you may regret it later.

[JohnnyMo]

Man, I'm learning so much differential geometry for my physics research paper. Being free to learn at vaguely my own pace feels so goddamn good, particularly when it's something interesting in its own right. Plus, I get to make fun diagrams in photoshop.

[Krinkels]

What's the paper about?

[JohnnyMo]

Anisotropic spacetimes, i.e. universes which don't look the same in every direction.

[Krinkels]

Anyone else write this?
[url]http://math.scu.edu/putnam/[/url]

[JohnnyMo]

A function whose derivative is zero almost everwhere which is strictly increasing

fuck this analysis shit

[Number-41]

but how

[JohnnyMo]

[QUOTE=Number-41;43117455]but how[/QUOTE]

wait I think this is better

[url]http://www.math.sc.edu/~howard/Notes/fubini.pdf[/url]

[editline]8th December 2013[/editline]

Also:

[B]Professor H, Algebraic Topology[/B]

"If this was a 300-level analysis class, we'd probably have to be very careful about how we set up this proof, but we're so much more sophisticated than that."

I do quite like how the further you go in mathematics, the less professors seem to care about very precise details

[Falubii]

Fubini is a funny name. That's what I took away from that proof.

[Number-41]

[QUOTE=JohnnyMo1;43118185]wait I think this is better

[url]http://www.math.sc.edu/~howard/Notes/fubini.pdf[/url]

[editline]8th December 2013[/editline]

Also:

[B]Professor H, Algebraic Topology[/B]

"If this was a 300-level analysis class, we'd probably have to be very careful about how we set up this proof, but we're so much more sophisticated than that."

I do quite like how the further you go in mathematics, the less professors seem to care about very precise details[/QUOTE]

"almost everywhere", does that mean everywhere except at the discontinuities?

Are there (non piecewise) continuous examples? Maybe something like the continuous-everywhere but differentiable-nowhere function?

[JohnnyMo]

It means at all but a countable set of points. There are indeed continuous examples. (what does it matter if it's piecewise?) The one I initially posted was continuous but I didn't think it was demonstrated very well. I don't know if it was differentiable everywhere though.

[JohnnyMo]

I have a strong desire to paste this into my last algebraic topology homework and hand it in tomorrow.

[IMG]http://i44.tinypic.com/25u5p8n.jpg[/IMG]

[Number-41]

When is reductio ad absurdum valid? My complex analysis course gives this weird example.

1 is the largest non-zero natural number.

[QUOTE]Proof:

assume there is an N > 1 (i.e. 1 is not the largest non-zero number). Multiply both sides with N:

N^2 > N

so N is not the largest natural number because N^2 is larger. This is a contradiction, therefore 1 is the largest natural number. [/QUOTE]

Where is the mistake? Or is this solid logic applied to an invalid example? I feel dumb :(

Edit: it starts on false premises, it assumes there actually exists a largest natural number. Now I feel even dumber.

[Joey90]

[QUOTE=Number-41;43240462]When is reductio ad absurdum valid? My complex analysis course gives this weird example.

1 is the largest non-zero natural number.

Where is the mistake? Or is this solid logic applied to an invalid example? I feel dumb :(

Edit: it starts on false premises, it assumes there actually exists a largest natural number. Now I feel even dumber.[/QUOTE]
a.k.a. Proof by Contradiction - it's always valid.

But as you say, if you disprove a statement, it just means some part of it is not true, although it can be easy to miss the bit that is if you aren't careful...

[JohnnyMo]

[QUOTE=Number-41;43240462]When is reductio ad absurdum valid? My complex analysis course gives this weird example.

1 is the largest non-zero natural number.

Where is the mistake? Or is this solid logic applied to an invalid example? I feel dumb :(

Edit: it starts on false premises, it assumes there actually exists a largest natural number. Now I feel even dumber.[/QUOTE]

Well it certainly proves there is no largest natural number greater than one! But that doesn't prove that one is the greatest. As we all know, Muhammad Ali is, in fact, the greatest.

[mastoner20]

[;y=\frac{Ln(\frac{x}{m}-sa)}{r^{2}};]
guys.

[JohnnyMo]

[IMG]http://i39.tinypic.com/24y4hw0.gif[/IMG]

[editline]20th December 2013[/editline]

[I]you're welcome[/I]

[mastoner20]

Yes, yes. I think you continued a step or two beyond what I was getting at (though I'm a few days early, but screw it).

[JohnnyMo]

spoiler: I know what it says

[Number-41]

So you visit Reddit eh?

[mastoner20]

Actually only on seldom occasion. An old professor emailed it to me by mistake somehow thinking I was still in one of his classes. Where he got it I have no idea.