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ALevel培训经济备考:需求的交叉弹性

今日要给我们解说的Cross elasticity of demand也是AS经济中我们最早接触的三个Elasticities之一,它也是很根底但常常考到的常识,应该做到彻底理解并且娴熟记忆有关的内容。

小编建议我们要常常模仿剖析并且推出相关定论,这样对考试中遇到类似问题后的思考进程很有协助。

▎Cross elasticity of demand的界说为:

It measures the responsiveness of quantity demanded of a product A when there is a change in the price of a related product B。

也便是说,当product B的价格发生变化时,将会对product A的需求数量形成多大的影响。

▎计算公式为:

% Of change in quantity demanded of product A / % of change in the price of a related product B。

这儿XED的value分为两种状况评论,一种是相互为Complements的products,比如CD player和CD。

ALevel培训经济备考


When the price of CD player decreases,

The quantity demanded for CD player and CD both increase;

When the price of CD player increases,

The quantity demanded for CDplayer and CD both decrease.

因为互为补足物的产品,假如其间一件产品的价格上涨,两者的需求数量将会一起跌落,反之亦然。

所以,Complements的XED value一定会是Negative的。

另一种是相互为Substitutes的products,比如Apple juice和orange juice。

When the price of apple juice increases,

The quantitydemanded for it will decrease,

And the quantity demanded for the relatively cheaper orange juice will increase;

When the price of apple juice decreases,

The quantity demanded for it will increase,

And the quantity demanded for the relatively more expensive

Orange juice will decrease.

互为替代品的产品,假如一种产品的价格上涨,另一种产品的价格将会变得相对廉价,而相对廉价的产品的需求数量将会上涨,另一个则会降低。所以,Substitutes的XED value一定会是positive的。

ALevel培训经济备考


综上所述,经过XED value的正负号,我们也能够得知两个Products之间的关系了。

一起,根据XED value的绝对值大小,又能够将其分成四类。(以下数字悉数为Assumption)

(1)  XED=-3 (Elastic)

Two products are close compliments,

Such as: CD playerand CD.

(2)  XED=-0.2 (Inelastic)

Two products are distant compliments,

Such as red wine and cheese.

(3)  XED=2.6 (Elastic)

Two products are close substitutes,

Such as pepsi and coke.

(4)  XED=0.3 (Inelastic)

Two products are distant substitutes,

Such as mineralwater and beer.

According to the extent(absolute value) of XED,

How closely the two products are related can be determined.

以上便是这次XED精讲的内容了,在将YED解说完之后,同学们能够好好收拾一下PED,XED和YED这三个Elasticities的内容。
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