A decisão da empresa competitiva de contratar mão de obra

For a competitive firm, the VMPL curve represents the additional revenue earned from hiring each worker. Since the firm maximizes profit by hiring workers until VMPL equals the market wage, the VMPL curve directly reflects the firm's demand for labor at each wage level. This relationship makes VMPL the firm's labor demand curve.

A firm stops hiring when the value of the marginal product of labor equals the prevailing market wage rate. If VMPL exceeds the wage, hiring another worker increases profit. If VMPL falls below the wage, the worker costs more than they generate in revenue, so hiring stops. This profit-maximizing point occurs where the VMPL curve intersects the wage line.

Hiring a worker whose VMPL is below the prevailing wage rate decreases firm profit. The worker adds less additional revenue than the cost to hire them. Therefore, the firm would increase total profit by laying off such workers until VMPL again equals the wage rate, restoring profit-maximizing equilibrium.

In a perfectly competitive labor market, individual firms are wage-takers. They can hire any number of workers at the prevailing market wage without affecting that wage. This creates a perfectly elastic (horizontal) labor supply curve for the firm, meaning the wage rate remains constant regardless of how many workers the firm hires.

Diminishing marginal product of labor means VMPL decreases as more workers are hired. This declining VMPL eventually falls to equal the market wage, determining the optimal number of workers to hire. Without diminishing returns, firms would continue hiring indefinitely, but the declining VMPL ensures a profit-maximizing stopping point.

Marginal profit equals VMPL minus the wage rate. When marginal profit is positive, hiring additional workers increases total profit. The firm continues hiring as long as marginal profit remains positive. Hiring stops when marginal profit reaches zero, which occurs where VMPL equals the wage, maximizing the competitive firm's total profit.

The competitive profit maximizing firm determines optimal workforce size by comparing the value of the marginal product of labor to the market wage at each employment level. The firm hires workers until VMPL equals the wage rate. This equilibrium point, shown graphically where the VMPL curve intersects the wage line, represents maximum profit.