# How do you find the sum of the infinite geometric series 1+ 3/5+9/25+37/125+........?

Nov 19, 2015

Use the formula for the infinite sum only if the common ratio is less than 1.

#### Explanation:

Geometric Sum $= {a}_{1} / \left(1 - r\right)$

Where, ${a}_{1}$ is the first term and $r$ is the common ratio .

Geometric Sum $= \frac{1}{1 - \frac{3}{5}} = 2.5$

Hope that helped