若给定一组证券,那么对于某一个特定的投资者来说,最佳证券组合应当位于()。
A.其无差异曲线族中的任意一条曲线上
B.其无差异曲线族与该组证券所对应的有效集的切点上
C.无差异曲线族中位置最高的一条曲线上
D.该组证券所对应的有效边缘上的任意一点
A.总需求曲线向左上方倾斜,表明价格水平越低,需求总量越小
B.总需求曲线向右下方倾斜,表明价格水平越高,需求总量越小
C.总需求曲线向右下方倾斜,表明价格水平越低,需求总量越大
D.总需求曲线描述了与每一价格水平相对应的均衡的支出或收入
E.总需求曲线表示社会的需求总量和价格水平之间的同方向的关系
假设你在管理一座营运成本基本上为零的收费桥。过桥需求的Q由P=15-(1/2)Q给出。
(1)画出过桥服务的需求曲线。
(2)如果不收费,会有多少人通过该桥?
(3)如果过桥费是5美元,相对应的消费者剩余的损失是多少?
(4)该收费桥的运营方打算把价格上升至7美元。在这一相对较高的价格上,会有多少人通过该桥?该收费桥的收益是上升还是下降了?从你的答案出发,你对需求弹性有何判断?
(5)求与价格从5美元上升到7美元相对应的消费者剩余的损失。
Suppose you are in charge of a toll bridge that costs essentially nothing to operate. The demand for bridge crossing Q is given by P=15-(1/2)Q.
a. Draw the demand curve for bridge crossings.
b, How many people would cross the bridge if there were no toll?
C. What is the loss of consumer surplus associated with a bridge toll of $ 5?
d. The toll - bridge operator is considering an increase in the toll to $7. Al this higher price ,how many people would cross the bridge? Would the toll bridge revenue increase or decrease? What does your answer tell you about the elasticity of demand?
e. Find the lost consumer surplus associated with the increase in the price of the toll from $5to $7.
A.该商品的弹性不等于斜率,但等于斜率的倒数
B.在该需求曲线与坐标轴交点的线段上,中点处的需求价格弹性为1
C.价格较高的点弹性比价格较低的点弹性大(绝对值)
D.价格较高的点弹性比价格较低的点弹性小(绝对值)
E.该商品具有不变的弹性
在习题1的基础上加入外国,其需求曲线为: D*= 80-20P,供给曲线为: S* =40+20P。
a.推导并绘出外国的出口供给曲线,同时计算没有贸易时外国的小麦价格。
b.如果本国和外国进行贸易,且运输成本为零。计算自由贸易时的均衡点,与之对应的世界价格是多少?贸易量又是多大?
Now add Foreign, which has a demand curve
D*=80-20P
and a supply curve
S*=40+20P
a. Derive and graph Foreign's export supply curve and find the price of wheat that would prevail in Foreign in the absence of trade.
b. Now allow Foreign and Home to trade with each other, at zero transportation cost. Find the equilibrium under free trade. What is the world price? What is the volume of trade?