Find the radius of convergence for f(x)=∑n=0∞(2n)!(n!)2xnf(x) = \sum_{n=0}^{\infty} \frac{(2n)!}{(n!)^2} x^nf(x)=∑n=0∞(n!)2(2n)!xn.
1/41/41/4
111
444
1/21/21/2