a. If z = f(x, y) has continuous second order partial derivatives, and x = r2 + s and y = 2rs, find (10 marks) arz b. The functions R = Al and V = Tlr determine the resistance and volume of a wire in terms of its length I and cross-sectional radius r(where A is a constant of the material). If we consider these equations as specifying I and r as functions of A and R. Use Jacobians to find OR (10 marks)