Question

Find the sum of the first five terms of the geometric sequence: - 1, - 6, - 36

Answer 1

The sum of the first five terms of the geometric sequence is -1555

Sum of geometric sequence

The formula for calculating the sum of geometric sequence is expressed as:

$S_n=\frac{a(r^n-1)}{r-1}$

where

r is the common ratio = 6/1 = 6

a is the first term = -1

n = 5 (number of terms)

Substitute

$S_5=\frac{-1(6^5-1)}{6-1}\\S_5=\frac{-7776+1}{5}\\S_5=-1555$

Hence the sum of the first five terms of the geometric sequence is -1555

Learn more on sum of sequence here; brainly.com/question/2142410

#SPJ1