Question

If there are 6 terms in a series then find find the sum of geometric series 2 6 18 54

Answer 1

Given,

A G.P with 6 terms 2, 6, 18, 54,...

To Find,

The sum of the terms of G.P.

Solution,

The formula for calculating the sum of n terms of a G.P is

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

In the given G.P

a= 2

r= 6/2= 3

n= 6

So,

S = 2(3⁶-1)/(3-1)

S = 2(729-1)/2

S = 728

Hence, the sum of six terms of the G.P is 728.