The demand curve embodies the trade-off a firm must navigate between price and quantity. A firm's desire for high prices and high quantities to maximize profit is constrained by the fact that raising the price will reduce the number of consumers willing to buy. Therefore, the demand curve acts as the firm's feasible frontier, outlining all viable combinations of price (P) and quantity (Q). A profit-maximizing firm will always select a point on this frontier because, for any given quantity, the highest possible price—and thus the highest profit—is found on the demand curve itself. [1] This makes the curve the central constraint in the firm's optimization problem. [1]