Derive a general expression for the sum of the first terms of a geometric progression…

MATHEMATICS · Subjective · A Level · Mathematics · Sequences and series · Sequences and series

Problem

Derive a general expression for the sum

S_n

of the first

n

terms of a geometric progression whose first term is

a

and common ratio is

r\,(r\neq 1)

. Your final answer should be in terms of

a,\,r

and

n

only.