Convergent Complex Series/Examples/((-1)^n + i cos n theta) over n^2

Example of Convergent Complex Series
The series $\displaystyle \sum_{n \mathop = 1}^\infty a_n$, where:
 * $a_n = \dfrac {\paren {-1}^n + i \cos n \theta} {n^2}$

is convergent.