Hello everyone!

I'm trying to understand how to work with PDEs in Maple by solving a basic PDE such as the wave equation, along with conditions at t = 0 in terms of arbitrary functions. I stumbled upon the very same example, included in the Maple Online help at this page under the part "Three Textbook Examples":

I tried to copy and paste the code and execute it, but to no avail: it seems like pdsolve doesn't give me any other result than a blank space, unlike in the example reported in the Online help. Can anyone tell me if (and where) I am doing wrong? Is it possible that my version of Maple (Maple 13) may not be compatible with the procedures required by this example?

 A warm thank you to whoever will help me!

Hello everyone!

I'm pretty new with Maple. I think I've understood the way Maple handles differentiation fairly well, but upon a specific request from my PhD tutor I have to perform a task which is giving me a hard time. 

My question is: is in any way possible to express a derivative of a function or expression in terms of the function itself?
I'll try to explain myself with an example: let f(x) and f'(x) be the function and its first derivative:

Instead of expressing f'(x) in the way shown, I'd like to express it as a function of f(x), such as in the following:

I would apply the same process to the higher order derivatives, if possible.

A huge thank you to whoever will help me!