3. Two Input Production FunctionsFor the rst function given below, derive the expression for the marginal product of x, the marginal product of y and the technical rate of substitution, graph three isoquants and determine whether the technology exhibits increasing, constant or decreasing returns to scale. For the second production function, you only need to graph the isoquants and determine whether the technology exhibits increasing, constant ordecreasing returns to scale.(a) f (x, y) = 5x 4 y 4(b) f (x, y) = min (x, 3y)