# Relationship between marginal cost and short run supply curve

### Short-run and Long-run Supply Curves (Explained With Diagram)

Because it says, in the short run a firm has to cover it's variable costs to But then how does that all link up to the marginal cost curve being the supply curve?. A perfectly competitive firm's supply curve is that portion of its marginal cost curve that lies above the minimum of the average variable cost curve. A perfectly. Hence, the short-run supply curve of a firm coincides with that portion of the short- run marginal cost curve which lies above the minimum point of the short-run.

Consider three key points: The law of diminishing marginal returns gives the marginal cost curve a positive slope.

An increase in the price, moves the profit-maximizing quantity to a higher point on the positively-sloped marginal cost curve, and a larger production quantity. A decrease in the price, moves the profit-maximizing quantity to a lower point on the positively-sloped marginal cost curve, and a smaller production quantity.

Working a Graph To illustrate, consider the production and supply decision made by Phil the zucchini grower, a hypothetical firm. Because Phil is one of gadzillions of zucchini producers, each producing identical products and each with a relatively small part of the overall market, he has no market control. As such, Phil is a price taker. He must react to the price determined by the interaction of market demand and market supply, making adjustments in his own production to accommodate higher or lower market prices.

Short-Run Supply This graph displays Phil's U-shaped cost curves representing his zucchini production. Note that all three curves average total costaverage variable cost, and marginal cost are U-shaped.

The marginal cost curve is U-shaped as a direct consequence of increasing, then decreasing marginal returns.

## Supply Curve of a Firm and Industry (With Diagram)

As a profit-maximizing zucchini producer, Phil produces the quantity of zucchinis that equates the going market price with marginal cost. Phil's supply response to changing prices can be observed by What might Phil do if he faces different prices. Consider a higher price. This higher price induces Phil to increase his quantity supplied from 7 to almost 8. Once again, a higher price motivates Phil to increase his quantity supplied.

Does Phil reduce the quantity supplied if the price declines? Up to a point. If the price falls below this level, then Phil shuts down production in the short run, incurring a lost equal to total fixed cost. The conclusion from this analysis is that the marginal cost curve that lies above the average variable cost is Phil's short-run supply curve.

A click of the [Short-Run Supply] button highlights Phil's zucchini supply curve. Only Perfect Competition This short-run supply curve explanation relies on Phil being a perfectly competitive price taker.

Measures of Capital Short-Run Supply In determining how much output to supply, the firm's objective is to maximize profits subject to two constraints: Consumer demand determines the price at which a perfectly competitive firm may sell its output. The costs of production are determined by the technology the firm uses.

The firm's profits are the difference between its total revenues and total costs. Total revenue and marginal revenue. A firm's total revenue is the dollar amount that the firm earns from sales of its output. If a firm decides to supply the amount Q of output and the price in the perfectly competitive market is P, the firm's total revenue is A firm's marginal revenue is the dollar amount by which its total revenue changes in response to a 1-unit change in the firm's output. Hence, in a perfectly competitive market, the firm's marginal revenue is just equal to the market price, P.

### AmosWEB is Economics: Encyclonomic WEB*pedia

A firm maximizes its profits by choosing to supply the level of output where its marginal revenue equals its marginal cost. When marginal revenue exceeds marginal cost, the firm can earn greater profits by increasing its output. When marginal revenue is below marginal cost, the firm is losing money, and consequently, it must reduce its output. Profits are therefore maximized when the firm chooses the level of output where its marginal revenue equals its marginal cost. To illustrate the concept of profit maximization, consider again the example of the firm that produces a single good using only two inputs, labor and capital.

## Why Is a Supply Curve Referred to as a Marginal Cost?

Assume that this firm is competing with many other firms in a perfectly competitive market. The firm's costs of production for different levels of output are the same as those considered in the numerical examples of the previous section, Theory of the Firm. These costs, along with the firm's total and marginal revenues and its profits for different levels of output, are reported in Table. Hence, the firm maximizes its profits by choosing to produce exactly 29 units of output. The marginal revenue, marginal cost, and average total cost figures reported in the numerical example of Table are shown in the graph in Figure.

The firm's equilibrium supply of 29 units of output is determined by the intersection of the marginal cost and marginal revenue curves point d in Figure. The firm's profits are therefore given by the area of the shaded rectangle labeled abed.