sympy/sympy — pull request #946 by povik (2012-01-09 19:46:55+00:00)
Title: [GCI 2011] Fix issue 2882: integration of 1/(1+x**2) works but 1/(1+u**2) fails

`log_to_real` used regular symbols instead of dummy ones. Changing this fixes the [issue 2882](http://code.google.com/p/sympy/issues/detail?id=2882)