How to define a funciton without the explicit defination in Maple?

Question

I want to define a funtion in Maple like:

g(t,r,theta,phi)

but without the explicit defination. Thus, when I try to run

diff(g,t)

I hope it can give(only the formular, not(also it cant) the value)

$g_t(t,r,theta,phi)$

or

$\frac{d g(t,r,theta,phi)}{dt}$

I know mathematica can do this, but I want to use the DifferentialGeometry module in Maple.

Thanks you all. Best wishes.

Answer 1

In fact, diff knows only expressions not functions, so it is

> diff(g(r,t,theta,phi),t);

You can possibly try this

> g:=G(r,t,theta,phi);
> diff(g,t);

But you won't be able to do much with $g$ anyway.