sympy/sympy — pull request #1503 by zanzibar7 (2012-08-22 01:21:38+00:00)
Title: Improve trig evaluation2

New code for evaluating rational*pi arguments to sin and cos. sin(pi/12),
sin(pi/15), and sin(pi/85), and others. This version may return very large
radical expressions. There is a comment showing where to bail if only simple
expressions are desired.

This is an updated version of the code I posted in relation to
issue 2949. http://code.google.com/p/sympy/issues/detail?id=2949

Second attempt. Removed uneed and distracting changes, in response
to criticism. (my branches were a mess. Still getting the hang of this.
Did some probably ill-advised stuff to clear my head. Will avoid committing
to master next-time.)