AFAIK, general Fréchet derivatives aren't available in any computer algebra system. You would have to hand roll something to expand the chain rule. Generally, the existence of such a derivative isn't available. For fun I tried your example in Mathematica and even there you get a recursion limit error.
-- Andy On Sat, Oct 30, 2010 at 7:16 AM, Philippe <[email protected]> wrote: > Hi, > > I am new to sympy. > I try to derive an equation of that form: T = k * x' > x if a function of time ; x = f(t) > x' is diff(x, t) > > I would like to get > T2 = diff(T, x') > T3 = diff(T2, t) > > Is it possible ? > I checked the documentation, but couldn't find a way to do that. > > Thanks for helping ! > Philippe > > PS: I try to get it with > T = m * f(t) > print diff(T, f(t)) > does not work :/ > ValueError: Invalid literal: f(t) is not a valid variable > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
