For the series ∑n=1∞xnn2\sum_{n=1}^{\infty} \frac{x^n}{n^2}∑n=1∞n2xn, find the interval of convergence.
(−1,1)(-1, 1)(−1,1)
[−1,1)[-1, 1)[−1,1)
[−1,1][-1, 1][−1,1]
(−1,1](-1, 1](−1,1]