在线指导ap课程辅导价格

AP宏观经济学重点概念：弹性

弹性是AP经济学考试必考的一个知识点，下面我用几道题目来解释一下这一章的知识要点。

1. Use the following diagram to answer the next question.

Refer to the diagram. Between the prices of $10 and $8, the price elasticity of demand is:

A) .5

B) .9

C) 1.11

D) 2

解释：我们要学会用弹性公式中的中位法(middle point method) 来计算弹性，分子为数量变化，分母为价格变化。

(22 – 18) / 20 ÷ (10 – 8) / 9 = .9.

2. Use the following diagram to answer the next question.

Refer to the diagram. Suppose total revenue at price P3 is the same as at price P2. Then, over the price range from P2 to P3, demand is:

A) relatively elastic

B) relatively inelastic

C) unit elastic

D) perfectly elastic

解释：如果总收入不变，需求变化和数量变化一定保持一致，这是单位弹性(unit elasticity)