## Thinking Mathematically (6th Edition)

$a_n=a_1 \cdot r^{n-1}$; $\text{first term}$; $\text{common ratio}$
Recall: In a geometric sequence, the $n^{\text{th}}$ term $a_n$ of is given by the formula: $$a_n=a_1\cdot r^{n-1}$$ where $a_1$=first term $r$=common ratio Thus, the missing expressions (in order) in the given statements are: $a_n=a_1 \cdot r^{n-1}$; first term; common ratio