Chapter 12 Sequences and Series - 12.5 Use Recursive Rules with Sequences and Functions - Guided Practice for Examples 1 and 2 - Page 828: 2

$a_{0}=162$ $a_{1}=81$ $a_{2}=40.5$ $a_{3}=20.25$ $a_{4}=10.125$

The first five terms are indexed from 0 to 4: $a_{0}=162$ $a_{1}=0.5\cdot a_{0}=81$ $a_{2}=0.5\cdot a_{1}=81/2=40.5$ $a_{3}=0.5\cdot a_{2}=81/4=20.25$ $a_{4}=0.5\cdot a_{3}=81/8=10.125$