Question

A geometric sequence is defined by the equation An=(2)5-2n. What are the first three terms of the sequence and what is the common ratio,r?

Answer 1

First term = (2)5^(-2*1) =2/25

2nd term = (2)5^(-2*2) = 2/ 625

3rd term = 2(5)^(-2*3) = 2/ 15625

If we divide the 3rd term by the 2nd term or the 2nd term by the first we get the common ratio

Common ratio = 1/25 or 0.04 as a decimal fraction.