完全競爭&外部性...請高手幫忙.... - 經濟

※ 引述《idtonychung (小鍾)》之銘言：
: 題目是這樣子的
: Suppose that the oil industry in Utopia is perfectly competitive and that all
: firms draw oil from a single (and practically inexhaustible)pool. Each
: competitor believes that he or she can sell all the oil he or she can produce
: at a stable world price of $10 per barrel and that the cost of operating a
: well for one year is $1,000. Total output per year (Q) of the oil field is a
: function of the number of wells (N) operating in the field. In particular,
: Q=500N-N^2 and the amount of oil produced by each well (q) is given by
: q=Q/N=500-N.
: a. Describe the equilibrium output and the equilibrium number of wells in
: this perfect competitive case. Is there a divergence between private and
: social marginal cost in the industry?

perfectly competitive下,個別廠商利潤為0

P*q=10*(500-N)=profit=cost=1000


: b. Suppose that the government nationalizes the oil field. How many oil
: wells should it operate? What will total output be? What will the output per
: well be?

Max total profit
= Max P*Q-1000*N

: c. As an alternative to nationalization, the Utopian government is
: considering an annual license fee per well to discourage overdrilling. How
: large should this license fee be to promote the industry to drill the optimal
: number of wells?

解出上題的Q之後,可以算出個別的q
在此q之下,個別廠商會有超額利潤,
為了防止其他廠商進入市場造成社會效率損失
所以要把他們的超額利潤榨乾
P*q=10*(500-N)=profit=cost=1000+license fee

: 老實說這題我苦思不得其解，a小提我是在猜用極大化Q，這樣社會的總收益應該會最大，

並不會

: 後面兩題就真的沒有頭緒了....

隨便寫不知道有沒有算錯...

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