On Saturday, September 13, 2014 11:18:49 PM UTC+2, Chris Maness wrote: > > Is it possible for sage to use an undefined function such that: > > diff(f(x(t),y(t)),t) yields the definition of the total derivative? > > I'm not sure about Sage itself, but since SymPy is technically part of Sage, this should count:
import sympy as sy t = sy.Symbol("t") f = sy.Function("f") x = sy.Function("x") y = sy.Function("y") y_dot = f(x(t), y(t)).diff(t) sy.pprint(y_dot, use_unicode=True) d ⎛ ∂ ⎞│ d ⎛ ∂ ⎞│ ──(x(t))⋅⎜───(f(ξ₁, y(t)))⎟│ + ──(y(t))⋅⎜───(f(x(t), ξ₂))⎟│ dt ⎝∂ξ₁ ⎠│ξ₁=x(t) dt ⎝∂ξ₂ ⎠│ξ₂=y(t) -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.