Which series converges FASTEST (terms decrease most rapidly)?
∑n=1∞1n2\sum_{n=1}^{\infty} \frac{1}{n^2}∑n=1∞n21
∑n=1∞1n!\sum_{n=1}^{\infty} \frac{1}{n!}∑n=1∞n!1
∑n=1∞12n\sum_{n=1}^{\infty} \frac{1}{2^n}∑n=1∞2n1
∑n=1∞1n3\sum_{n=1}^{\infty} \frac{1}{n^3}∑n=1∞n31