Comment #48 on issue 1816 by asmeurer: Adding partial derivatives and taking derivatives with respect to functions
http://code.google.com/p/sympy/issues/detail?id=1816
Or in concrete terms, why is it that diff(expr, cos(2*x)) works but diff(expr, 2*cos(x)) raises?
Because cos(2*x) can unambiguously be replaced in the original expression with the simple rule of "exact" substitution like discussed on the list.
-- You received this message because you are subscribed to the Google Groups "sympy-issues" group. To post to this group, send email to sympy-issues@googlegroups.com. To unsubscribe from this group, send email to sympy-issues+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy-issues?hl=en.
