Comment #2 on issue 1494 by asmeurer: eq.subs fails for Derivative(u(t)**2,
t**2)
http://code.google.com/p/sympy/issues/detail?id=1494
The bug was that this didn't raise an exception until it got to the subs
line (maybe that's not what the OP meant though :), but this has been fixed:
In
Status: New
Owner: plaes800
Labels: Type-Defect Priority-Medium
New issue 1494 by plaes800: eq.subs fails for Derivative(u(t)**2, t**2)
http://code.google.com/p/sympy/issues/detail?id=1494
Following code fails with traceback:
#!/usr/bin/python
from sympy import *
t = Symbol(t)
u, F =
