## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$a_n=7(2)^{n-1}$
The $n^{th}$ term of a geometric sequence is given by the formula: $a_n=a_1r^{n-1}$ where $r$=common ratio and $a_1$= the first term The common ratio of a geometric sequence is equal to the quotient (ratio) of any term and the term before it: $\ r = \dfrac{a_n}{a_{n-1}}$ or, $r=\dfrac{a_2}{a_1}$ Here, we have: $a_1=7$ and $a_2=14$, so $r=\dfrac{14}{7}=2$ Therefore, the general formula for the sequence is $a_n=7(2)^{n-1}$