完全競爭市場上的廠商均衡.ppt

1、完全競爭市場上的廠商均衡,7.2 The Equilibrium of the Firm under Perfect Competition,教學(xué)目標(biāo)Objectives： 了解完全競爭的市場條件 掌握完全競爭市場的需求曲線和收益曲線 掌握完全競爭市場的短期均衡條件 掌握完全競爭市場的長期均衡條件 知識點(diǎn)Knowledge： 完全競爭的市場條件、完全競爭市場的需求曲線和收益曲線 完全競爭市場的短期均衡和長期均衡條件 技能點(diǎn)Skills： 繪制完全競爭市場均衡圖,price taker advertising market opportunities ideal type advantages

2、shortcomings government Normal profit Supernormal profit least-cost economic profit abnormal profit homogeneous product economies of scale industry,專業(yè)詞匯Professional terms,一、完全競爭的含義與條件,Assumptions l Firms are price taker. l There is complete freedom of entry into the industry for new firms. l All fir

3、ms produce an identical product. The product is homogeneous, so there is no branding and advertising. l Producers and consumers have perfect knowledge of the market. That is, producers are fully aware of prices, costs and market opportunities. Consumers are fully aware of the price, quantity and ava

4、ilability of the product.,Nevertheless, despite the lack of real-world cases, the model of perfect competition plays a very important role in economic analysis and policy. Its major relevance is as an ideal type. Many on the political right argue that perfect competition brings a number of important

5、 advantages. The model can thus be used as a standard against which to judge the shortcomings of real world industries. It can help government to formulate policies towards industry.,一、完全競爭的含義與條件,實(shí)現(xiàn)完全競爭的條件包括： 第一，市場上有許多生產(chǎn)者與消費(fèi)者，每一個生產(chǎn)者的銷售量與消費(fèi)者的購買量只占市場極小的份額。 第二，市場上的產(chǎn)品是同質(zhì)的，即不存在產(chǎn)品差別 。 第三，資源完全自由流動。 第四，市場信息

6、是暢通的。,一、完全競爭的含義與條件,The short run and the long run lThe short run under perfect competition The period during which there is too little time for new firms to enter the industry. l The long run under perfect competition The period of time that is long enough for new firms to enter the industry. Normal

7、 profit The opportunity cost of being in business: the profit that could have been earned in the next best alternative business. It is counted as a cost of production. Supernormal profit (also known as pure profit, economic profit, abnormal profit or simply profit) The excess of total profit above n

8、ormal profit.,二、完全競爭市場上的需求和收益曲線,三、完全競爭市場上的短期均衡,三、完全競爭市場上的短期均衡,廠商獲得正常利潤 (normal profit),三、完全競爭市場上的短期均衡,廠商獲得超額利潤 (supernormal profit),三、完全競爭市場上的短期均衡,廠商遭受虧損,三、完全競爭市場上的短期均衡,四、完全競爭市場上的長期均衡,五、對完全競爭市場的評論,In many industries, firms may have to be quite large if they are to experience the full potential econo

9、mies of scale. But perfect competition requires there to be many firms. Firms must therefore be small in most for economies of scale. Once a firm expands sufficiently to achieve economies of scale, it will usually gain market power. It will be able to undercut the prices of smaller firms, which will

10、 thus be driven out of business. Perfect competition is destroyed. Perfect competition could only exist in any industry, therefore, if there were no (or virtually no) economies of scale.,Perfect competition and the public interest,There are a number of features of perfect competition which, it could

11、 be argued, benefit society: l Price equals marginal cost, which has important implications for the allocation of resources between alternative products. l If a firm becomes less efficient than other firms, it will make less than normal profits and be driven out of business. If it is more efficient,

12、 it will earn supernormal profits. Thus the competition between firms will act as a spur to efficiency. l Similarly, the desire for supernormal profit, and the desire to avoid loss, will encourage the development of new technology.,Perfect competition and the public interest,lThere is no point in ad

13、vertising under perfect competition, since all firms produce a homogeneous product.This and the previous two factors will lead to low AC curves, and hence to an economical use of the nations scarce resources. lFor any given technology, the firm, in the long run, will produce at the least-cost output

14、. l The consumer gains from low prices, since not only are costs kept low, but also there are no long-run supernormal profits to these costs. lIf consumer tastes change, the resulting price change, the resulting price change will lead firms to respond (purely out of self-interest). An increased consumer demand will call forth extra supply with only a short-run increase in profit.,五、對完全競爭市場的評論,第一，社會供給與需求相等，使資源得到最優(yōu)配置，生產(chǎn)者的生產(chǎn)不會有不足或過剩，消費(fèi)者的需求也得到了充分滿足。 第二，在長期均衡時所達(dá)到的平均成本處于最低點(diǎn)，表明可以通過完全競爭與資源的自由流動