### Labor, cost function

A firm has a cost function given by the following: c(w1, w2, y)= w1w2y^2/(w1+w2) where the wi's are the prices of the factors (inputs) x1 and x2 respectively, and y is output. a) Is this a legitimate cost function? b) Find the firm's production function, y= f(x1, x2). c) From the cost function derive the firm's