Sum ∑_{k=0}^{n−1} ar^k (r ≠ 1).

Sum ∑_{k=0}^{n−1} ar^k (r ≠ 1).

A a(1 − r^n)/(1 − r)

B a(1 − r^{n+1})/(1 − r)

C ar^n/(1 − r)

D a(r − r^n)/(1 − r)

Solution

Correct Answer: Option A