p.s. just remembering that you will always just get a single solution for dy/dx so you can return the answer rather than a list. It can all be encapsulated as:
def implicit_diff(eq, dep, ind): """Return d_dep/d_ind given eq(y) = 0 >>> import sympy as s >>> s.var('x y') (x, y) >>> eq=s.sympify('x^2+y^2 - 36') >>> implicit_diff(eq, y, x) >>> -x/y """ f=sympy.Function('f', dummy=True) eq=eq.subs(dep, f(ind)) return sympy.solve(eq.diff(ind), f(ind).diff(ind))[0].subs(f(ind), dep) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sympy?hl=en -~----------~----~----~----~------~----~------~--~---