Exercise 3 Page 315

The given rule means that, after the first term of the sequence, every term $a_n$ is the half of the previous term $a_{n-1}.$

First Six Terms of the Sequence: $\text{-}36,\text{-}18,\text{-}9,\text{-}\frac{9}{2},\text{-}\frac{9}{4},\text{-}\frac{9}{8}$
Graph: