1.perfect competition 理论上是在 normal profit 这个点上运作的, 就是经济利润为0 (long term).

而monopoly 可以把价格定在利润最大化的点上(不考虑其他因素-如政府政策等).就算不是利润最大话,也会CHARGE HIGHER PRICE THAN PERFECT COMPETITION. 因为什么,简单的说因为他要赚钱,而且他有能力赚钱. 因为他垄断市场,可以控制价格(firms in perfect competiton are price taker).

在不考虑其他因素的情况下,他可以把价格定在任何一个点上, 反之perfect competition 只能把价格定在 mr=mc=ar=ac=p 这个点上.也就是经济利润为0的这个点. do you believe a monopoly will make normal profit in long term? it is not a non-profit firm.

2 好久前学的,忘了,似乎是这样的.

要price discrimination 必须对该物品有一定的垄断力, 比如没有或少有 替代品, 相似品少等等.

市场必须可分,比如不同的年龄,性别,地域等对该物品的支付意愿不同.

等等.

the main aim of price discrinimation is to increase the total revenue or profit for supplier.不同的人群或地域的customer surplus 不同.

比如按年龄PRICE DISCRINIMATE. 正常的市场价格是$100. 学生$70(学生不怎么需要该产品) 老人$130(老人很需要该产品).这样那学生的consumer surplus increse 老人的下降.

第3提是只market fail 吗?不大明白原体.

考试提吗,楼主自己找资料啊,不要在这里考我门啊.

虽然我写的都是垃圾没什么用,单还是觉的这个忙不太应该帮.

呵呵楼主在那里学习啊.国外吗?以后多交流啊.

calvinnz well done.

i wanna give some supplement to the first one.

under the circumstance of perfect competition market, one producer determine his price addcording to the production at which point the marginal return equals to the marginal cost(better saying choose his marginal cost which is equals to the existing price).

this principle applies to a monopoly firm. but the difference is that the demand curve is the very MR curve in a competition market because of the constant price whereas, when a single producer holds the market he faces a demand curve with slope and therefor the demand curve is always above its marginal return curve(as regular).

suppose the cost is constant when the production is provided no matter whether it were supplied by a monopoly firm or a competition one, and that the production is given.

for a monopoly firm, at the point when the MR=MC, the quantity is determined, but the equilibrium price should be found on the demand curve, which is above the MR curve.

Therefore, when the MR is equal to the competition price, the monopoly price is to be higher than it.

[此贴子已经被作者于2006-4-16 18:35:40编辑过]