Is the series $\sum _{n=1}^{\infty } (-1)^n / {n^2}$ convergent or absolutely convergent? Is this series convergent or absolutely convergent? $$\sum _{n=1}^{\infty }\:(-1)^n \frac {1} {n^2}$$
Attempt:
I got this using Ratio Test: 
$$\lim_{n \to \infty} \frac{n^2}{(n+1)^2}$$

Hint: Use the integral test on $\sum_{k=1}^{\infty}\frac{1}{k^{2}}$.
Note that the ratio test is inconclusive in this case.
