Question

一个有关微观经济学的考研问题，求高人指点

Answer 1

这是寡头垄断里的卡特尔模型，结论是最大利润在各自的边际成本处，查看范里安的寡头，本书最精彩的地方。选C

cartel is simply a group of firms that jointly collude to behave like a single
monopolist and maximize the sum of their profits.
Thus the profit-maximization problem facing the two firms is to choose
their outputs Y1 and Y2 so as to maximize total industry profits:
This will have the optimality conditions
p(Yi + yi ) + �� [yi + yiJ = MC1 (yn
p(y􀄎 + yi) + �: [y􀄏 + yil = MC2 (Y2 ) '
The interpretation of these conditions is interesting. When firm 1 considers
expanding its output by 6..Y1 , it will contemplate the usual two effects:
the extra profits from selling more output and the reduction in profits from
forcing the price down. But in the second effect, it now takes into account
the effect of the lower price on both its own output and the output of the
other firm. This is because it is now interested in maximizing total industry
profits, not just its own profits.
The optimality conditions imply that the marginal revenue of an extra
unit of output must be the same no matter where it is produced. It follows
that MC1 (y1） = MC2 (y2 ) , so that the two marginal costs will be equal in
equilibrium. If one firm has a cost advantage, so that its marginal cost curve
always lies below that of the other firm, then it will necessarily produce
more output in equilibrium in the cartel solution.
The problem with agreeing to join a cartel in real life is that there

显示地不清楚，最优解 MC1 (y1） = MC2 (y2 )
哦，看错了，是两家厂商的边际成本和边际收益均相等，而不是各自的边际成本等于边际收益。因为此时感兴趣的不只是各自的利润最大化，而是整个行业的利润最大化
选D

Answer 2

假设图形法、排除法解题

直接画出X、Y企业的平均成本曲线，然后一个个选项排除

追问

那该选什么？