Alternating series test
= Alternating series test
{wiki}
If $a_n\geq0$ decreases to zero, then $\sum_{n=1}^{\infty}(-1)^na_n$ converges.
= Alternating series test
{wiki}
If $a_n\geq0$ decreases to zero, then $\sum_{n=1}^{\infty}(-1)^na_n$ converges.