# Definition:Geometric Sequence/Common Ratio

## Definition

Let $\sequence {x_n}$ be a geometric sequence in $\R$ defined as:

$x_n = a r^n$ for $n = 0, 1, 2, 3, \ldots$

The parameter:

$r \in \R: r \ne 0$

is called the common ratio of $\sequence {x_n}$.