Question

A geometric sequence is shown below. 3, 15, 75, 375,... What is the explicit formula for an=3⋅5nan=3⋅ an=5⋅3nan=5⋅ an=5⋅3n−1

Answer 1

The explicit formula for the given Geometric Progression is;

`\begin{gathered} a_n=ar^(n-1)\text{ , where a=3, r=}(15)/(3)=5,\text{ and n=?} \\ a_n=3.5^(n-1)\text{ (option C)} \end{gathered}`