（本题使用了基础微观经济学)本章讨论了有菜单成本的企业的价格调整决策。本题让你考虑在一个企业的简单情况

(本题使用了基础微观经济学)本章讨论了有菜单成本的企业的价格调整决策。本题让你考虑在一个企业的简单情况下对这一问题的进一步分析。

a．画出一个描述垄断企业的图形，包括向右下方倾斜的需求曲线和成本曲线。(为了简单起见，假设边际成本是不变的，因此成本曲线是一条水平线。)显示利润最大化的价格和数量；显示在这种最优状态代表利润和消费者剩余的面积。

b．现在假设企业事前宣布了略高于最优水平的价格。显示这一价格和销售量：显示代表价格过高所导致的利润损失的面积；显示代表消费者剩余减少的面积。

c．企业要通过比较降价的额外利润与菜单成本来决定是否降价。在作出这种决策时，企业忽略了的外部性是什么？在什么意义上说，企业的价格调整决策是无效率的？

(This problem uses basic microeconomics.) The chapter discusses the price-adjustment decisions of firms with menu costs. This problem asks you to consider that issue more analytically in the simple case of a single firm.

a．Draw a diagram describing a monopoly firm, including a downward-sloping demand curve and a cost curve. (For simplicity, assume that marginal cost is constant, so the cost curve is a horizontal line.) Show the profit-maximizing price and quantity. Show the areas that represent profit and consumer surplus at this optimum.

b．Now suppose the firm has previously announced a price slightly above the optimum. Show this price and the quantity sold. Show the area representing the lost profit from the excessive price. Show the area representing the lost consumer surplus.

c．The firm decides whether to cut its price by comparing the extra profit from a lower price to the menu cost. In making this decision, what externality is the firm ignoring？ In what sense is the firm's price-adjustment decision inefficient？