Use the ratio test to find the radius of convergence for ∑n=1∞n!⋅xn3n\sum_{n=1}^{\infty} \frac{n! \cdot x^n}{3^n}∑n=1∞3nn!⋅xn.
R=0R = 0R=0
R=3R = 3R=3
R=∞R = \inftyR=∞
R=1R = 1R=1