Which of the following is an example of a telescoping series?
∑n=1∞(1n+1−1n)\sum_{n=1}^{\infty} (\frac{1}{n+1} - \frac{1}{n})∑n=1∞(n+11−n1)
∑n=1∞n2\sum_{n=1}^{\infty} n^2∑n=1∞n2
∑n=1∞1n\sum_{n=1}^{\infty} \frac{1}{n}∑n=1∞n1
∑n=1∞2n\sum_{n=1}^{\infty} 2^n∑n=1∞2n