Partial fraction decomposition with cos() in the numerator

[Mr Davis 97]

Homework Statement

See below

Homework Equations

The Attempt at a Solution

I am looking at a particular integral, and to get started, my text gives the indication that one should use partial fraction decomposition with $\displaystyle \frac{\cos (ax)}{b^2 - x^2}$. Specifically, it says "then make a partial fraction expansion." However, I only learned the technique of partial fraction decomposition in the context of polynomials. I am not sure exactly what it is asking me to do.

 

[vela]

It just means to expand the $\frac{1}{b^2-x^2}$ part. The resulting factors will still be multiplied by the cosine.