Question

Write the explicit formula that represents the geometric sequence -2, 8, -32, 128

Answer 1

$a_{1}=-2 \\ \\ a_{2}=8 \\ \\ q= \frac{a_{2}}{a_{1}} \\ \\ q= \frac{8}{-2}=-4 \\ \\ a_{n}=a_{1}*q^{n-1} \\ \\ a_{n}=-2*-4^{n-1}$