@Preben Alsholm Ok, thank you again, I will keep this point in mind. The syntax in Maple is certainly more complicated than required for the previous software I used (Mathcad).

Thank you, this is very helpful. I appreciate the quick reply.

If I use f(a) rather than I(a) to lable the funciton, as I is used for complex numbers, the call sequence still does not run.

f(a):=int(exp(-x^2)*sin(a*x),x=0..infinity

I would be grateful for advice. Thank you.