Consider a firm with technology that can be represented by the following production function:

f(x1, x2) = min {x1, x2} + x2

Input 1 costs w1 > 0 per unit and input 2 costs w2 > 0 per unit.

(a) Draw the isoquant associated with an output of 4. Make sure to label any intercepts and slopes.

(b) Find the firm’s long-run cost function, c(w1, w2, y).