Let a(t) = 0.02t + 1. (a) Calculate the future value of an investment at t = 5 consisting of a payment of 1 now and a payment of 2 at t = 3. (b) Calculate the present value of an investment consisting of payments of 2 at times t = 1, 2, 3, 4. (c) Determine the force of interest at time t = 1