Question

What is the sum of the geometric sequence 1, 3, 9, if there are 11 terms?

Answer 1

The answer is 88,573

Answer 2

The sum of GP series is 88573

Explanation:

Given the geometric sequence

1, 3, 9,... 11 terms

we have to find the sum of 11 terms.

a=1, r=3, n=11

The formula for finite terms of GP is

`S_n=(a(1-r^n))/(1-r)`

`=(1(1-3^(11)))/(1-3)=(177146)/(2)=88573`

The sum of GP series is 88573