sympy/sympy — pull request #7476 by comer (2014-05-07 15:01:26+00:00)
Title: Tutorial finite diff derivs

This is a new version of the finite difference derivatives pull request. I think I want this to stick and the old one #7473 to be nuked. This happened when I had trouble pushing my work from yesterday to github this morning. Hopefully this is clean...sorry.