## Calculus (3rd Edition)

We have to calculate $\rho$: $$\rho=\lim _{n \rightarrow \infty}\left|\frac{a_{n+1}}{a_{n}}\right|=\lim _{n \rightarrow \infty}\left|\frac{1/5^{(n+1)}}{1/5^n}\right|=1/5 \lt 1$$ Thus the series converges.