Question

𝑎, 𝑎𝑅, 𝑎𝑅2, … , 𝑎𝑅𝑛−1 (2)
Find the sum of the geometric sequence in (2), denoted by
𝑆𝑛.
In finance problems, the number n may be the number of months or years. The number R is the compounding factor given by (1+r), related to the rate of interest, r. Each finance problem is unique and applying the geometric series formula upfront may lead to wrong answers.

Answer 1

i'm confuse with this question..can somebody help me?

Answer 2

Sn = a(1+R+R^2+...+R^(n -1)) a(R^n - 1)/(R-1) = a/r (R^n - 1)