Does the series ∑n=1∞1n2+1\sum_{n=1}^{\infty} \frac{1}{n^2 + 1}∑n=1∞n2+11 converge?
Yes, by comparison to ∑1n2\sum \frac{1}{n^2}∑n21
No, it diverges
Yes, by the ratio test
Inconclusive