Question

Find the sum of the first 10 terms in this geometric series.
1+3+9+27+...

Answer 1

29524

Explanation:

The sum of the first n terms is
`S_n=a_1(1-r^n)/(1-r)` where
`a_1` is the first term and r is the common ratio.

For the sequence in this question,
`a_1=1,\,r=3`.

`S_10=(1)(1-3^10)/(1-3)=(-59048)/(-2)=29524`