Question

A geometric sequence is defined by the explicit formula an=5(-4)^n-1 what is the recursive formula for the nth term of this sequence?

Answer 1

Hello,

$a_{n}=5*(-4)^{n-1}\\ a_{n-1}=5*(-4)^{n-2}\\\\ \dfrac{a_{n}}{a_{n-1}}=(-4)^{n-1-(n-2)}=-4\\\\ Formula\ is\ :\\ a_{n}=-4*a_{n-1}\\ a_{1}=5$