Which one of the following is the necessary and sufficient condition for the infinite…

MATHEMATICS · Single correct · AP · Calculus BC · Infinite Sequences and Series · Infinite Sequences and Series

Problem

Which one of the following is the necessary and sufficient condition for the infinite series

a+ar+ar^{2}+ar^{3}+\tfrac{}{}\cdots

to converge? (a)

|r|\le 1

(b)

r<1

(c)

|r|<1

(d)

r=0