1. (20 marks) Find and classify the critical points of the function f(x,y) = x3 + 313 - 3xy- 2. (20 marks) Find the determinant and inverse of the following matrices 3 0 2 (a)A=[1 7 0]; 0 3 4 1 0 1 (b)B= 5 3 0]- 5 2 4 3. (20 marks) Find the minimum value of f (x, y) = x2 + 312 subject to the constraint equation ng, y) = x231 = 16