Which of the following series converge absolutely?
∑n=1∞(−1)nn\sum_{n=1}^{\infty} \frac{(-1)^n}{n}∑n=1∞n(−1)n
∑n=1∞sin(n)n2\sum_{n=1}^{\infty} \frac{\sin(n)}{n^2}∑n=1∞n2sin(n)
∑n=1∞(−1)nn\sum_{n=1}^{\infty} \frac{(-1)^n}{\sqrt{n}}∑n=1∞n(−1)n
∑n=1∞(−1)nnn+1\sum_{n=1}^{\infty} \frac{(-1)^n n}{n+1}∑n=1∞n+1(−1)nn