Exercise 4 Page 318

• 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* a_(n-1).

We are given the recursive rule below. a_1=18, a_n=a_(n-1)+ 1 Since the recursive equation is of the form a_n=a_(n-1)+ d, it represents an arithmetic sequence.