Does ∑n=1∞n2n4+1\sum_{n=1}^{\infty} \frac{n^2}{n^4+1}∑n=1∞n4+1n2 converge?
Yes, by comparison to 1/n21/n^21/n2
No, by comparison to 1/n1/n1/n
No, by Ratio Test
Yes, by Integral Test