布兰查得宏观经济课件第5部分.ppt

彭更问曰：“後车数十乘，从者数百人，以传食於诸侯，不以泰乎？”（泰，甚也） 孟子曰：“非其道，则一箪食不可受於人。如其道，则舜受尧之天下，不以为泰。子以为泰乎？” 曰：“否！士无事而食，不可也。” 曰：“子不通功易事（事与功者，盖所作未成，则谓之事；事之成，则谓之功） ，以羡（馀也）补不足，则农有馀粟，女有馀布。子如通之，则梓、匠、轮、舆，皆得食於子。凡人当通功易事，乃可各以奉其用。 於此有人焉，入则孝，出则悌，守先王之道，以待後之学者，而不得食於子。子何尊梓、匠、轮、舆而轻为仁义者哉？” 曰：“梓、匠、轮、舆，其志将以求食也。君子之为道也，其志亦将以求食与？” 曰：“子何以其志为哉？其有功於子，可食而食之矣。且子食志乎，食功乎？”曰：“食志。” 曰：“有人於此，毁瓦画墁，其志将以求食也，则子食之乎？” 曰：“否。” 曰：“然则子非食志也，食功也。” ——孟子，滕文公章句下  The Goods Marketand the IS Relation Equilibrium in the goods market exists when production, Y, is equal to the demand for goods, Z. This condition is called the IS relation. In the simple model developed in chapter 3,we assume investment was constant, and the interest rate did not affect the demand for goods. The equilibrium condition was given by: Investment, Sales,and the Interest Rate In fact ,investment is far from constant .In this chapter, we capture the effects of two factors affecting investment: The level of sales (+) The interest rate (-) Determining Output Taking into account the investment relation above, the equilibrium condition in the goods market becomes: Determining Output The Determination of Output The Determination of Output Deriving the IS Curve The transmission mechanism(传导机制) of Figure 5 - 2 can be reason in words : step1:An increase in the interest rate leads to an decrease in investment. Step2:The decrease in investment leads to a decrease in output, stpe3: The decrease in output further decrease consumption and investment . In other words, the initial decrease in investment leads to a larger decrease in output through the multiplier effect(乘数效应). Deriving the IS Curve Deriving the IS Curve Using Figure 5-3, we can find the relation between equilibrium output and the interest rate. Panel 5-3(a) reproduces Figure 5-2. The interest rate i implies a level of output equal to Y. Panel 5-3(b) plots equilibrium output Y on the horizontal axis against the interest rate on the vertical axis. This re