Answer
If $\displaystyle \lim_{n\rightarrow\infty}a_{n}\neq 0$, then $\displaystyle \sum_{n=1}^{\infty}a_{n}$ diverges.
Work Step by Step
Th. 9.9, nth-Term Test for Divergence:
If $\displaystyle \lim_{n\rightarrow\infty}a_{n}\neq 0$, then $\displaystyle \sum_{n=1}^{\infty}a_{n}$ diverges.
