[trentonstrong]

Wow, thanks for posting this.

I was equally inspired during undergrad and grad school by Feynman's "unusual tools", and ended up checking out a copy of Advanced Calculus by Woods which was apparently the book he used to learn calculus in high school. If I recall correctly, Woods goes over integration by both differentiation and integration under the integral sign, including some interesting ways to set boundary conditions to get the answer you want. It's a nice book if you ever get the chance.

[acqq]

Thanks, here's the full Feynman's reference at the end of this article:

http://en.wikipedia.org/wiki/Differentiation_under_the_integ...

[nilaykumar]

This is going on my books to check out as _soon_ as I get to college list!