For the series ∑n=1∞xnnn\sum_{n=1}^{\infty} \frac{x^n}{n^n}∑n=1∞nnxn, find the radius of convergence RRR.
R=1R = 1R=1
R=0R = 0R=0
R=∞R = \inftyR=∞
R=eR = eR=e