Exercise 6 Page 318

We will use the following facts.

• The recursive equation for an arithmetic sequence is $a_n=a_{n-1}+d.$
• The recursive equation for a geometric sequence is $a_n=r\cdot a_{n-1}.$

We are given the recursive rule below. Since the recursive equation is of the form $a_n=r\cdot a_{n-1},$ it represents a geometric sequence.