# How do you find the sum of the finite geometric sequence of #Sigma 10(1/5)^n# from n=0 to 20?

##### 1 Answer

Oct 13, 2017

**(2 .d.p)**

#### Explanation:

First calculate the first three terms:

Find the common ratio:

The sum of a geometric sequence is:

Where **a** is the first term, **n** is the nth term and **r** is the common ratio.

So: