help with question 4

4. [20 points total] Harry lives for two periods 1 and 2. In period 1, he earns income yl, consumes c1, and buys bond b. Thus his budget constraint for period 1 is c1 + b = y1. We assume that he cannot sell bond, which gives an additional constraint: 5 = y1 c1 2 D. In period 2, he earns income yg, receives (1 + r) b from bond, and consumes (:2. Hence, his budget constraint for period 2 is given as 02 = 92 +(1 +195- His lifetime utility can be written as u (01) +51! (62}: i3 E (0,1) - Assuming 1 + r O > u\" and u." (D) = 00 (b) [10 points] a." > O, u\" > U, and u\" (U) = U