Question

What is the geometric series? Please evaluate. I will report if you copy.

Answer 1

9514 1404 393

Answer:

S9 = 52,429

Explanation:

The sum is given by the formula ...

`S_n=a_1*(r^n-1)/(r -1)`

The first term of this series is a1 = 1. The common ratio is r = -4/1 = -4. You want the sum for n = 9 terms. Putting these values into the formula gives ...

`S_(9)=1*((-4)^(9)-1)/((-4) -1)=(-262144-1)/(-5)=\boxed{52429}`