Determine the interval of convergence for ∑n=1∞xnn2\sum_{n=1}^{\infty} \frac{x^n}{n^2}∑n=1∞n2xn at the endpoints.
Converges only at x=0x=0x=0
Converges at x=1x=1x=1 only
Converges at x=1x=1x=1 and x=−1x=-1x=−1
Converges at x=−1x=-1x=−1 only