Well, seeing as b is a constant, that implies that as m goes through the different values, from one to infinity, b is unaffected. So, what can we do with it?

EDIT: If it isn't immediately evident why b remains unaffected as m goes through its different values, and what we can do with it, let's calculate a partial sum of this series. Let's find the sum for just

What do you notice about "a" and "b," as m goes from 1 to 3?