Question: A firm in perfect competition faces the following total cost function:
C = 250X - 20X2 + 2X3
(a) What is the firm's supply function?
(b) At what output is marginal cost minimised?
(c) What is the firm's long-run equilibrium output and, assuming that every firm has the same cost function, price?
(d) In this long-run equilibrium, what is the value of profits?
(e) The firm is now a monopolist, with demand curve p = 550 - 10X. What are equilibrium price, output and profit?