In this case, the marginal cost curve has a “swoosh” shape and the average total cost curve is U-shaped. The monopolist maximizes profit by producing the level of output at which MR = MC, given by point A, generating quantity Q_M. It finds its monopoly price, P_M, from the point on the demand curve directly above point A, point B here. The average total cost of Q_M is shown by point C. Profit is given by the area of the shaded rectangle.