Question

Find the sum of 6 terms of the series 2 + 6 + 18 + .....

Answer 1

a = 2

r = 3

n = 6

Sum of n terms of the GP

Sn = `(a(r^n - 1))/(r - 1)`

S₆ = `(2(3^6 - 1))/2`

= 729 − 1

= 728