Dear Maple users

Please help me correct this input:

> f := (c[A], c[B]) -> c[A]+c[B];
Error, invalid operator parameter name
    f Assign Typesetting:-mambiguous(

      (c[A]comma c[B]) rarr c[A] + c[B], 

      Typesetting:-merror(invalid operator parameter name))
> 

In Maple, c[A] is actually "c subscript A".

Thanks for help.

PS: Is...

Dear Maple Users

What am i doing wrong?

Dear Maple users

This might have been asked before, I'm asking because I believe the solution to my problem is simpler than what i found on google.

I have this problem:

Dear Maple Users

I wonder how I can use Maple to solve the problem:

for the potential \phi(r). The problem is from the artikle: http://en.wikipedia.org/wiki/Electric-field_screening

I'm particularly puzzled how to implement this differential operator and how to enter the Dirac delta function.

Thanks for any hints.

Dear Maple Users

I wonder if it is possible to somehow display what kind of substitution the integration tutor carried out. The tool is ultimately usefull, however it would be very instructive (in addition to the hints it's capable of giving) to see how a variable was "changed".

Is it possible somehow and how?

Thanks, Martin