How to find total derivative by using total derivative operator?

I have two functions and .

I want to find the total derivative of .

where is as given in the attached file

Answer 1

[Bjorn Gustavsson]

If you have the symbolic toolbox it is just to get to work:

syms x y t
syms u(x,y,t)
syms p(x,y,t)
dudx = diff(u*p,x) % etc...

Then just to add up the different derivatives.

HTH