Thanks for the detailed output. It helps me understand how Maple is behaving. But I still don't understand why Maple would evaluate the expression in Eq (10) to zero without knowing the value of r. It's almost as if Maple assumes r<0. If I explicitly assume r>0 then the expression in Eq (10) remains un-evaluated.  So I'm still a bit confused.

Thanks,

Francois

Thanks for the detailed output. It helps me understand how Maple is behaving. But I still don't understand why Maple would evaluate the expression in Eq (10) to zero without knowing the value of r. It's almost as if Maple assumes r<0. If I explicitly assume r>0 then the expression in Eq (10) remains un-evaluated.  So I'm still a bit confused.

Thanks,

Francois