題組內容

(6) Let $\{an\}$ be a real-valued sequence and let $\sigman = (a1 + \cdots + an)/n$.

(b) (10 %) Let $a_n = n^n/n!$. Show that

$$\lim_{n \to \infty} \frac{n}{(n!)^{1/n}} = e.$$