Earlier in this series, I gave three different methods of showing that
Since is independent of , I can substitute any convenient value of that I want without changing the value of . As shown in previous posts, substituting yields the following simplification:
To evaluate this integral, I need to find the four complex roots of the denominator:
To solve for , there are three separate cases that have to be considered: , , and . I’ll begin with the easiest case of . In this case, the integral is easy to evaluate:
This matches the expected answer of since I used the assumption that .