Definition:Geometric Sequence/Scale Factor

Definition
Let $\left \langle{x_n}\right \rangle$ be a geometric progression in $\R$ defined as:
 * $x_n = a r^{n-1}$ for $n = 1, 2, 3, \ldots$

The parameter:
 * $a \in \R: a \ne 0$

is called the scale factor of $\left \langle{x_n}\right \rangle$.