Which of the following describes the convergence of the series ∑n=1∞cos(nπ)(12)n\sum_{n=1}^{\infty} \cos(n\pi) (\frac{1}{2})^n∑n=1∞cos(nπ)(21)n?
Converges to −13-\frac{1}{3}−31
Converges to 13\frac{1}{3}31
Converges to −12-\frac{1}{2}−21
Diverges