PROBLEM 5 [points: 20] Find the closed-form formulas to each of the following recurrence relations and initial conditions. Use expand- guess-verify technique. Note: do expand and guess, but there is no need to verify (i.e. prove by mat yourself) induction – only if you want to check (a) an-3an-1, a,-2. (b) a,-an-1 + 2, a,-3.