MATLAB: Question about Symbolic Differentiation

Question

Hello,

If I write the following code:

syms x t
answer = diff(x,t)

then answer = 0.

Is it possible to declare that x is some unknown function of t, so that diff(x,t) will return dxdt instead of 0?

(I'm asking because I'm trying to use MATLAB to automatically derive differential equations for certain user input for a specific application.)

Thank you,

Kevin

Answer 1

If you have a fairly new version of MATLAB (R2011b I think was the first), then

syms x(t)
diff(x,t)