642 reputation
411
bio website
location Brooklyn, NY
age 33
visits member for 3 years, 1 month
seen Sep 22 at 4:46
Good Morning how are you, I'm dr jimbob
I'm interested in things.
I'm not a real dr,
But I am a real jim bob.

Have a PhD in Experimental High-Energy Physics, but left academia in mid-2010 to program professionally.

Mostly program/script in python, django, and jquery these days doing mostly web apps.

Also have experience programming in C, C++, java, haskell, php, and (bash) shell more in the past.

Linux as primary OS since 1999, ubuntu user since 2005 (Hoary).


Sep
24
awarded  Autobiographer
Aug
31
awarded  Yearling
Jun
10
comment 'Obvious' theorems that are actually false
@AnonymousPi $i = \exp\left(\frac{(4n + 1) \pi i}{2}\right)$ where $n \in {\Bbb N}$. Hence $i^i = \exp\left(\frac{-(4n + 1) \pi}{2}\right)$.
Apr
16
awarded  Nice Answer
Oct
9
awarded  Critic
Sep
27
revised Good books and lecture notes about category theory.
fixed link (old link 404s)
Aug
31
awarded  Yearling
Jun
11
awarded  Nice Question
May
23
answered Can we get just $3$ from $\pi$?
May
23
comment Can we get just $3$ from $\pi$?
OP asked: "Without using π again"
May
6
comment Prove $a+b+c+d $ is composite
Note this does not work if you include 0 in the natural numbers. (Obvious counterexample: a = 0, b=3, c=0, d=4, so ab = cd = 0, but a+b+c+d=7 which is prime).
Feb
11
answered 2013th derivative of a trigonometric function
Jan
11
revised How to make two vectors orthogonal?
added 227 characters in body
Jan
11
revised How to make two vectors orthogonal?
Very sloppy bad math on my part.
Jan
11
revised How to make two vectors orthogonal?
added 112 characters in body
Jan
11
answered How to make two vectors orthogonal?
Jan
11
comment How to make two vectors orthogonal?
It's not Gramm-Schmidt. It's Gram-Schmidt (assuming you want to take a set of vectors that spans some space and create a new set of orthogonal vectors - typically also normalized - that spans the same space).
Jan
10
comment How to solve this calculus problem?
@MaoYiyi - There an infinite number of potential functions $f(x)$ that satisfy the given property (e.g., if you assume a form of Ax^4 + Bx^3 + Cx^2 + Dx + E; then A=-134/2475, B = 3622/2475, C=-31924/2475, D=106937/2475, E= -7369/165; or you could assume Ax^10+Bx^8+Cx^6+Dx^4+Ex^2 and get a totally different answer that meets the criteria). E.g., you can give a rough estimate of f'(2.5) based on f(2), f(3) -- even if its more of an average value of f'(x) between 2 and 3.
Jan
10
comment How to solve this calculus problem?
@proximal - I was trying to not suggest evaluate the limit, but to see f'(x) = lim h->0 (f(x+h) - f(x-h))/(2h) we can approximate f'(x) ~ (f(x+h) - f(x-h))/(2h) at several points, exactly as you said. Just was trying to leave it as "hints".
Jan
10
answered How to solve this calculus problem?