2 2. (10 points) A consumer has the following utility function u(x1, X2) = 4 In(x1) + 3 In(x2), defined for x1 > 0 and X2 > 0. (a) Find the consumer's marginal utility functions uj and u2. (b) Find all second order partial derivatives for the consumer's utility function: u11, U22 and u12. Present the Hessian matrix for the consumer's utility function. (c) Based on the Hessian matrix in part (b), can you tell whether the consumer's utility function is strictly concave? Why or why not