1. In predicting future sales of a product, one assumption is to say that the amount sold next year will be the average of the amount sold this year and last year. Suppose that

an is the amount sold in year n.

(a) Find a recurrence relation for an.

(b) Solve the recurrence relation if a0 = a1 = 1.

What i have found so far is that "an = 2an+1 - an-1"

AM I ON THE RIGHT TRACK? PLEASE HELP ASAP!