1. The problem statement, all variables and given/known data Determine the convergence or divergence of the series: series from n = 1 to infinity of cos (3npi). ((please rewrite in LaTex... idk how?)). 3. The attempt at a solution I rewrote the series to the following: series from n = 1 to infinity of (-1)^n ... because the terms of the above series go to -1, 1, -1, 1, -1. The first requirement of the alternative series test, is to take the limit as n approaches infinity of the sequence a(sub n). Is a(sub n) just equal to 1 in this case? Doesn't that mean it diverges by the nth term test for divergence because the limit is 1 and not equal to 0?