Given the series ∑n=1∞n!xnnn\sum_{n=1}^{\infty} \frac{n! x^n}{n^n}∑n=1∞nnn!xn, find the radius of convergence RRR.
R=1R = 1R=1
R=eR = eR=e
R=1eR = \frac{1}{e}R=e1
R=0R = 0R=0