5) For each of the power series below, find the radius and interval of conver-gence. \sum_{n=0}^{\infty} \frac{n^{2} x^{n}}{3^{2 n+1}} \sum_{n=0}^{\infty} \frac{(-3)^{n}(x-1)^{n}}{2 n^{2}+1}