Question: Chain rule for PDE

Hello!

I am working with very complicated PDE's, and I am stuck with the chain rule.

The variable k is dependent on T.

T is dependent on x and y.

The expression for k is quite complicated, and will change depending on the application.

So, we are trying to not include the expression for k in Maple, but only that k=k(T), and carry this information throught the calculations.  I do need to calculate the derivative and carry this information as well.

Even though I have used 'alias' to tell Maple that k and T are functions, the result of diff(k,x)=0, and I was expecting to have diff(k,x)=diff(k,T)*diff(T,x) (chain rule).

Does anybody know how to do this?

Thanks a lot!

> restart;
> alias(T = T(x, y));
                                      T
> alias(k = k(T));
                                    T, k
>
> diff(k, x);
                                      0