A series of numbers or terms in which the ratio of any term to the subsequent term is constant. For example, 1, 4, 16, 64, 256,… has a common ratio of 4. In general, a geometric series can be written:
a + ar + ar2+… + arn−1
and the sum of n terms is:
a(rn − 1)/(r − 1).
Subjects: Biological Sciences — Mathematics.