e, find the first 5 terms of the sum and compute Sn

Question

find the first 5 terms of the sum and compute S_n .

n

_∑(3/2)^i

_i=1

Answer 1

This is a geometric series with first term = 3/2 and r=3/2.

The sum is (arⁿ⁺¹-a₁)(r-1)