Question

What is the recursive rule for this geometric sequence? 1/2 ,−2, 8, −32,

Answer 1

an = an-1 * -4

Explanation:

First we need to find the common ratio

r = second term / first term

= -2/ (1/2) = -4

The recursive formula is

an=an−1 * r

an = an-1 * -4