Question

determine convergence of divergence using any method..

Answer 1

\[\sum_{n=1}^{\infty} (-1)^{n+1} / (2n+1)!\]

Answer 2

absolute value method right!?

Answer 3

or should I compare to 1/2n

Answer 4

Whenever you have that (-1)^n expression, usually either you consider the absolute series or you use the alternating series (Leibniz) test.