Poles within a circle

1. Nov 7, 2005

David Laz

I need to use residue calculus to evaluate:
$$\oint_C {\frac{{e^z }}{{\cosh z}}} dz$$
where C is the circle |z|=5
My only problem (which is a stupid one) is working out how many poles the function has inside the circle. I know its going to have them at pi*i/2 + pi*i*k. This is probably a really stupid question, but I've left alot of this course till the last minute. :(

2. Nov 7, 2005

David Laz

Worked it out. I'm an idiot for overlooking something so simple.