Question

What is the sum of the geometric sequence -4,24,-144...if there are 8 term? A.-959,781 B. 29,637 C. 26,661 D. 959,780 PLEASE HELP

Answer 1

it is d because I know it guys trust me it is easy.

Answer 2

The sum of 8 terms of series is 959,780

D is correct

Explanation:

Given: -4, 24, -144, ......

There are 8 terms.

We need to find the sum of 8 terms.

First term, a=-4

Common ratio, r=-6

`a_n=-4\cdot(-6)^(n-1)`

Sum of 8 term

`Sum=a_1+a_2+a_3+a_4+a_5+a_6+a_7+a_8`

`Sum=\sum_(n=1)^(8)a_n`

`Sum=-4+24-144+864-5184+31104-186624+1119744`

`Sum=959,780`

Hence, The sum of 8 terms of series is 959,780