## anonymous 5 years ago How do you find the sum of 1/(8^n) from n=1 to infinity? I know it equals 8/49 but I don't know how/why

1. anonymous

$\sum_{n=1}^{+\infty}\frac{1}{8^n}=\frac{1}{8}+\frac{1}{8^2}+\frac{1}{8^3}+\cdots =\frac{1}{8}\cdot\frac{1}{1-1/8}=\frac{1}{7}$

2. anonymous

sorry i meant the sum of n/8^n

3. anonymous

8/49

4. anonymous

thank you :)