6 firms_competitive课件.ppt

6 Firms in Competitive Markets zjx_hn2004@ In this chapter, look for the answers to these questions 美国的石油大王洛克菲勒是怎样起家的？ WHAT IS A COMPETITIVE MARKET? A perfectly competitive market has the following characteristics: 1.There are many buyers and many sellers in the market.(市场上有许多买者和许多卖者) 2.The goods offered by the various sellers are largely the same.（各个卖者提供的物品大体上是相同的） 3.Firms can freely enter or exit the market.（企业可以自由地进入或退出市场） Because of 1 2, each buyer and seller is a “price taker” – takes the price as given The Demand Curve of a Competitive Firm The Revenue of a Competitive Firm Total revenue for a firm is the selling price times the quantity sold.（一家企业的总收益是销售价格乘以销售数量） TR = P ? Q Total revenue is proportional to the amount of output.（总收益与产量同比例变动） The Revenue of a Competitive Firm Average revenue tells us how much revenue a firm receives for the typical unit sold.（平均收益告诉我们企业从销售的普通一单位中得到了多少收益） Average revenue is total revenue divided by the quantity.（平均收益是总收益除以产量） The Revenue of a Competitive Firm In perfect competition, average revenue equals the price of the good. The Revenue of a Competitive Firm Marginal revenue is the change in total revenue from an additional unit sold.（边际收益是增加一单位销售量引起的总收益的变动） MR =?TR/ ?Q Table 1 Total, Average, and Marginal Revenue for a Competitive Firm TR、AR、MR PROFIT MAXIMIZATION AND THE COMPETITIVE FIRM’S SUPPLY CURVE The goal of a competitive firm is to maximize profit. 竞争企业的目标是利润最大化。 竞争企业利润最大化的均衡条件 Table 2 Profit Maximization: A Numerical Example PROFIT MAXIMIZATION AND THE COMPETITIVE FIRM’S SUPPLY CURVE When MR MC increase Q When MR MC decrease Q When MR = MC Profit is maximized. Profit Maximization for a Competitive Firm Figure 1 Profit Maximization for a Competitive Firm How does a competitive firm determine its profit Figure 2 Profit as the Area between Price and Average Total Cost Figure 2 Profit as the Area between Price and Average Total Cost Figure 2 Profit as the Area between Price and Average Total Cost 狡猾的农场主