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多恩布什宏观经济学课件一、引言多恩布什宏观经济学是由美国经济学家鲁迪格·多恩布什提出的宏观经济学理论体系。
该理论以市场供需为基础，强调政府干预对经济波动的影响，并提出了“多恩布什曲线”来描述政府支出与税收政策对经济波动的影响。
本课件将简要介绍多恩布什宏观经济学的基本原理和核心观点，以帮助读者更好地理解和应用该理论。
二、多恩布什宏观经济学的基本原理1.市场供需与价格机制多恩布什宏观经济学认为，市场供需关系是决定价格和资源配置的关键因素。
当市场上的需求增加时，价格会上升，从而刺激生产者增加供给，以满足市场需求。
相反，当市场上的需求减少时，价格会下降，导致生产者减少供给。
通过价格机制的自我调节，市场能够实现资源的有效配置。
2.政府干预与经济波动多恩布什宏观经济学强调政府干预对经济波动的影响。
政府通过调整支出和税收政策，可以影响经济的总需求和总供给。
例如，政府增加支出可以刺激总需求，促进经济增长；而政府减少支出或增加税收则会抑制总需求，导致经济放缓。
政府干预的目的在于通过调整总需求和总供给，实现经济的稳定和可持续发展。
三、多恩布什曲线多恩布什曲线是多恩布什宏观经济学中的重要概念，用于描述政府支出与税收政策对经济波动的影响。
多恩布什曲线是一条向下倾斜的曲线，表示政府支出与税收政策对总需求的影响程度。
1.政府支出增加当政府增加支出时，总需求会增加，导致多恩布什曲线向右移动。
这种政策可以刺激经济增长，提高就业水平，但也可能导致通货膨胀和财政赤字的增加。
2.税收减少当政府减少税收时，个人和企业的可支配收入增加，总需求也会增加，导致多恩布什曲线向右移动。
这种政策可以刺激消费和投资，促进经济增长，但也可能导致财政赤字的增加。
四、多恩布什宏观经济学在实践中的应用多恩布什宏观经济学在实践中有着广泛的应用。
政府可以通过调整支出和税收政策，来应对经济波动和实现经济目标。
1.经济增长与就业政府可以通过增加支出来刺激总需求，促进经济增长和就业。
宏观经济学多恩布什第10版教材下载及考研视频网课多恩布什《宏观经济学》（第10版）网授精讲班【教材精讲＋考研真题串讲】目录多恩布什《宏观经济学》（第10版）网授精讲班【郑炳老师讲授的完整课程】【共41课时】多恩布什《宏观经济学（第10版）》网授精讲班【王志伟老师讲授的部分课程】【共28课时】电子书（题库）•多恩布什《宏观经济学》（第10版）【教材精讲+考研真题解析】讲义与视频课程【39小时高清视频】•多恩布什《宏观经济学》（第10版）笔记和课后习题详解•试看部分内容导论与国民收入核算第1章导论1.1 复习笔记1宏观经济学宏观经济学主要讨论总体经济的运行，具体包括：经济增长问题——收入、就业机会的变化；经济波动问题——失业问题，通货膨胀问题；经济政策——政府能否、以及如何干预经济，改善经济的运行。
2．微观经济学与宏观经济学的关系（1）二者的联系第一，微观经济学和宏观经济学互为补充。
微观经济学是在资源总量既定的条件下，通过研究个体经济活动参与者的经济行为及其后果来说明市场机制如何实现各种资源的最优配置；宏观经济学则是在资源配置方式既定的条件下研究经济中各有关总量的决定及其变化。
第二，微观经济学是宏观经济学的基础。
这是因为任何总体总是由个体组成的，对总体行为的分析自然也离不开个体行为的分析。
第三，微观经济学和宏观经济学都采用了供求均衡分析的方法。
微观经济学通过需求曲线和供给曲线决定产品的均衡价格和产量，宏观经济学通过总需求曲线和总供给曲线研究社会的一般价格水平和产出水平。
（2）二者的区别第一，研究对象不同。
微观经济学研究的是个体经济活动参与者的行为及其后果，侧重讨论市场机制下各种资源的最优配置问题，而宏观经济学研究的是社会总体的经济行为及其后果，侧重讨论经济社会资源的充分利用问题。
第二，中心理论不同。
微观经济学的中心理论是价格理论，宏观经济学的中心理论是国民收入决定论。
第三，研究方法不同。
微观经济学的研究方法是个量分析，宏观经济学的研究方法是总量分析。
CHAPTER 10MONEY, INTEREST, AND INCOMEAnswers to Problems in the Textbook:Conceptual Problems:1. The model in Chapter 9 assumed that both the price level and the interest rate were fixed. But the IS-LM model lets the interest rate fluctuate and determines the combination of output demanded and the interest rate for a fixed price level. It should be noted that while the upward-sloping AD-curve in Chapter 9 (the [C+I+G+NX]-line in the Keynesian cross diagram) assumed that interest rates and prices were fixed, the downward-sloping AD-curve that is derived at the end of Chapter 10 from the IS-LM model lets the price level fluctuate and describes all combinations of the price level and the level of output demanded at which the goods and money sector simultaneously are in equilibrium. 2.a. If the expenditure multiplier (α) becomes larger, the increase in equilibrium income caused by a unitchange in intended spending also becomes larger. Assume investment spending increases due to a change in the interest rate. If the multiplier α becomes larger, any increase in spending will cause a larger increase in equilibrium income. This means that the IS-curve will become flatter as the size of the expenditure multiplier becomes larger.If aggregate demand becomes more sensitive to interest rates, any change in the interest rate causes the [C+I+G+NX]-line to shift up by a larger amount and, given a certain size of the expenditure multiplier α, this will increase equilibrium income by a larger amount. As a result, the IS-curve will become flatter.2.b. Monetary policy changes affect interest rates and this leads to a change in intended spending, whichis reflected in a change in income. In 2.a. it was explained that a steep IS-curve means either that the multiplier α is small or that desired spending is not very interest sensitive. Therefore, an increase in money supply will reduce interest rates. However, this does not result in a large increase in aggregate demand if spending is very interest insensitive. Similarly, if the multiplier is small, then any change in spending will not affect output significantly. Therefore, the steeper the IS-curve, the weaker the effect of monetary policy changes on equilibrium output.3. Assume that money supply is fixed. Any increase in income will increase money demand and theresulting excess demand for money will drive the interest rate up. This, in turn, will reduce the quantity of money balances demanded to bring the money sector back to equilibrium. But if money demand is very interest insensitive, then a larger increase in the interest rate is needed to reach a new equilibrium in the money sector. As a result, the LM-curve becomes steeper.Along the LM-curve, an increase in the interest rate is always associated with an increase in income. This means that an increase in money demand (due to an increase in income) has to be offset by a decrease in the quantity of money demanded (due to an increase in the interest rate) to keep the money sector in equilibrium. But if money demand becomes more income sensitive, a smaller change in income is required for any specific change in the interest rate to keep the money sector in equilibrium. Therefore, the LM-curve becomes steeper as money demand becomes more income sensitive.4.a. A horizontal LM-curve implies that the public is willing to hold whatever money is supplied at anygiven interest rate. Therefore, changes in income will not affect the equilibrium interest rate in the money sector. But if the interest rate is fixed, we are back to the analysis of the simple Keynesian model used in Chapter 9. In other words, there is no offsetting effect (or crowding-out effect) to fiscal policy.14.b. A horizontal LM-curve implies that changes in income do not affect interest rates in the money sector.Therefore, if expansionary fiscal policy is implemented, the IS-curve shifts to the right, but the level of investment spending is no longer negatively affected by rising interest rates, that is, there is no crowding-out effect. In terms of Figure 10-3, the interest rate not longer serves as the link between the goods and assets markets.4.c. A horizontal LM-curve results if the public is willing to hold whatever money balances are suppliedat a given interest rate. This situation is called the liquidity trap. Similarly, if the Fed is prepared to peg the interest rate at a certain level, then any change in income will be accompanied by an appropriate change in money supply. This will lead to continuous shifts in the LM-curve, which is equivalent to having a horizontal LM-curve, since the interest rate will never change.5. From the material presented in the text we know that when intended spending becomes more interestsensitive, then the IS-curve becomes flatter. Now assume that an increase in the interest rate stimulates saving and therefore reduces the level of consumption. This means that now not only investment spending but also consumption is negatively affected by an increase in the interest rate. In other words, the [C+I+G+NX]-line in the Keynesian cross diagram will now shift down further than previously and the level of equilibrium income will decrease more than before. In other words, the IS-curve has become flatter.This can also be shown algebraically, since we can now write the consumption function as follows:C = C* + cYD - giIn a simple model of the expenditure sector without income taxes, the equation for aggregate demand will now beAD = A o + cY - (b + g)i.From Y = AD ==> Y = [1/(1 - c)][A o - (b + g)i] ==>i = [1/(b + g)]A o - [(1 - c)/(b + g)]YTherefore, the slope of the IS-curve has been reduced from (1 - c)/b to (1 - c)/(b + g).6. In the IS-LM model, a simultaneous decline in interest rates and income can only be caused by a shiftof the IS-curve to the left. This shift in the IS-curve could have been caused by a decrease in private spending due to negative business expectations or a decline in consumer confidence. In 1991, the economy was in a recession and firms did not want to invest in new machinery and, since consumer confidence was very low, people were not expected to increase their level of spending. In the IS-LM diagram the adjustment process can be described as follows:I o↓ ==> Y ↓ (the IS-curve shifts left) ==> m d↓ ==> i ↓ ==> I ↑ ==> Y ↑. Effect: Y ↓ and i ↓ .2ii1i221Technical Problems:1.a. Each point on the IS-curve represents an equilibrium in the expenditure sector. Therefore the IS-curvecan be derived by settingY = C + I + G = (0.8)[1 - (0.25)]Y + 900 - 50i + 800 = 1,700 + (0.6)Y - 50i ==>(0.4)Y = 1,700 - 50i ==> Y = (2.5)(1,700 - 50i) ==> Y = 4,250 - 125i.1.b. The IS-curve shows all combinations of the interest rate and the level of output such that theexpenditure sector (the goods market) is in equilibrium, that is, intended spending is equal to actual output. A decrease in the interest rate stimulates investment spending, making intended spending greater than actual output. The resulting unintended inventory decrease leads firms to increase their production to the point where actual output is again equal to intended spending. This means that the IS-curve is downward sloping.1.c. Each point on the LM-curve represents an equilibrium in the money sector. Therefore the LM-curvecan be derived by setting real money supply equal to real money demand, that is,M/P = L ==> 500 = (0.25)Y - 62.5i ==> Y = 4(500 + 62.5i) ==> Y = 2,000 + 250i.1.d. The LM-curve shows all combinations of the interest rate and level of output such that the moneysector is in equilibrium, that is, the demand for real money balances is equal to the supply of real money balances. An increase in income will increase the demand for real money balances. Given a fixed real money supply, this will lead to an increase in interest rates, which will then reduce the quantity of real money balances demanded until the money market clears. In other words, the LM-curve is upward sloping.1.e. The level of income (Y) and the interest rate (i) at the equilibrium are determined by the intersectionof the IS-curve with the LM-curve. At this point, the expenditure sector and the money sector are both in equilibrium simultaneously.From IS = LM ==> 4,250 - 125i = 2,000 + 250i ==> 2,250 = 375I ==> i = 6==> Y = 4,250 - 125*6 = 4,250 - 750 ==> Y = 3,500Check: Y = 2,000 + 250*6 = 2,000 + 1,500 = 3,5003i125 ISLM62,000 3,500 4,250 Y2.a. As we have seen in 1.a., the value of the expenditure multiplier is α= 2.5. This multiplier αisderived in the same way as in Chapter 9. But now intended spending also depends on the interest rate, so we no longer have Y = αA o, but ratherY = α(A o - bi) = (1/[1 - c + ct])(A o - bi) ==> Y = (2.5)(1,700 - 50i) = 4,250 - 125i.2.b.This can be answered most easily with a numerical example. Assume that government purchasesincrease by ∆G = 300. The IS-curve shifts parallel to the right by==> ∆IS = (2.5)(300) = 750.Therefore IS': Y = 5,000 - 125iFrom IS' = LM ==> 5,000 - 125i = 2,000 + 250i ==> 375i = 3,000 ==> i = 8==> Y = 2,000 + 250*8 ==> Y = 4,000 ==> ∆Y = 500When interest rates are assumed to be constant, the size of the multiplier is equal to α = 2.5, that is, (∆Y)/(∆G) = 750/300 = 2.5. But when interest rates are allowed to vary, the size of the multiplier is reduced to α1 = (∆Y)/(∆G) = 500/300 = 1.67.2.c. Since an increase in government purchases by ∆G = 300 causes a change in the interest rate of 2percentage points, government spending has to change by ∆G = 150 to increase the interest rate by 1 percentage point.2.d. The simple multiplier α in 2.a. shows the magnitude of the horizontal shift in the IS-curve, given achange in autonomous spending by one unit. But an increase in income increases money demand and the interest rate. The increase in the interest rate crowds out some investment spending and this has a dampening effect on income. The multiplier effect in 2.b. is therefore smaller than the multiplier effect in 2.a.3.a. An increase in the income tax rate (t) will reduce the size of the expenditure multiplier (α). But as themultiplier becomes smaller, the IS-curve becomes steeper. As we can see from the equation for the IS-curve, this is not a parallel shift but rather a rotation around the vertical intercept.Y = α(A o - bi) = [1/(1 - c + ct)](A o - bi) ==> i = (1/b)A o - (α/b)Y = (1/b)A o - (1/b)[1 - c + ct]Y 3.b. If the IS-curve shifts to the left and becomes steeper, the equilibrium income level will decrease. Ahigher tax rate reduces private spending and this will lower national income.3.c. When the income tax rate is increased, the equilibrium interest rate will also decrease. The adjustmentto the new equilibrium can be expressed as follows (see graph on the next page):t up ==> C down ==> Y down ==> m d down ==> i down ==> I up ==> Y up. Effect: Y ↓ and i ↓45i 1i 2214.a. If money demand is less interest sensitive, then the LM-curve is steeper and monetary policy changesaffect equilibrium income to a larger degree. If money supply is assumed to be fixed, the adjustment to a new equilibrium in the money sector has to come solely through changes in money demand. If money demand is less interest sensitive, any increase in money supply requires a larger increase in income and a larger decrease in the interest rate in order to bring the money sector into a new equilibrium.i ii 1 i 1 2 2i 20 120 12The adjustment process in each of the two diagrams is the same; however, in the case of a more interest-sensitive money demand (a flatter LM-curve), the change in Y and i will be smaller.(M/P) up ==> i down ==> I up ==> Y up ==> m d up ==> i up Effect: Y ↑ and i ↓Section 10-5 derives the equation for the LM-curve and the equation for the monetary policy multiplier asi = (1/h)[kY - (M/P)] and (∆Y)/∆(M/P) = (b/h)γrespectively. If money demand becomes more interest sensitive, the value of h becomes larger and the slope of the LM-curve becomes flatter, while the size of the monetary policy multiplier becomes smaller.4.b. An increase in money supply drives interest rates down. This decrease in interest rates will stimulateintended spending and thus income. If money demand becomes less interest sensitive, a larger increase in income is required to bring the money sector into equilibrium. But this implies that the overall decrease in the interest rate has to be larger, given that the interest sensitivity of spending has not changed.5. The price adjustment, that is, the movement along the AD-curve, can be explained in the followingway: With nominal money supply (M) fixed, real money balances (M/P) will decrease as the price level (P) increases. There is an excess demand for money and interest rates will rise. This will lead toa decrease in investment spending and thus the level of output demanded will decrease. In otherwords, the LM-curve will shift to the left as real money balances decrease.6. In the classical case, the AS-curve is vertical. Therefore, any increase in aggregate demand due toexpansionary monetary policy will, in the long run, not lead to any increase in output but simply lead to an increase in the price level. An increase in money supply will first shift the LM-curve to the right.This implies a shift of the AD-curve to the right. Therefore we have excess demand for goods and services and prices will begin to rise. But as the price level rises, real money balances will begin to fall again, eventually returning to their original level. Therefore, the shift of the LM-curve to the right due to the expansionary monetary policy and the resulting shift of the AD-curve will be exactly offset by a shift of the LM-curve to the left and a movement along the AD-curve to the new long-run equilibrium due to the price adjustment. At this new long-run equilibrium, the level of output and interest rates will not have changed while the price level will have changed proportionally to the nominal money supply, leaving real money balances unchanged. In other words, money is neutral in the long run (the classical case).7.a. An increase in the demand for money will shift the LM-curve to the left, raising the interest rate andlowering the level of output demanded. As a result, the AD-curve will also shift to the left. In the Keynesian case, the price level is assumed to be fixed, that is, the AS-curve is horizontal. In this case, the decrease in income in the AD-AS diagram is equivalent to the decrease in income in the IS-LM diagram, since there is no price adjustment, that is, the real balance effect does not come into play. 7.b. An increase in the demand for money will shift the LM-curve to the left, raising the interest rate andlowering the level of output demanded. As a result, the AD-curve will also shift to the left. In the classical case, the level of output will not change, since the AS-curve is vertical. In this case, the shift in the AD-curve will simply be reflected in a price decrease, but the level of output will remain unchanged. The real balance effect causes the LM-curve to shift back to its original level, since the price decrease causes an increase in real money balances.Additional Problems:1. True or false? Explain your answer.“A decrease in the marginal propensity to save implies tha t the IS-curve will become steeper.”False A decrease in the marginal propensity to save (s = 1 - c) is equivalent to an increase in the marginal propensity to consume (c), which, in turn, implies an increase in the expenditure multiplier ( ). But with a larger expenditure multiplier, any increase in investment spending due to a decrease in the interest rate will lead to a larger increase in income. Therefore the IS-curve will become flatter and not steeper.2. True or false? Explain your answer.“If the c entral bank keeps the supply of money constant, then the money supply curve is vertical, which implies a vertical LM-curve.”6False. Equilibrium in the money sector implies that real money supply is equal to real money demand, that is,m s = M/P = m d(i,Y).This implies that any increase in income (Y) will increase the demand for money. To bring the money sector back into equilibrium, interest rates (i) have to rise simultaneously to bring the quantity of money demanded back to the original level (equal to the fixed supply of money). Therefore, to keep the money sector in equilibrium, an increase in income must always be associated with an increase in the interest rate and the LM-curve must be upward sloping.3. "Restrictive monetary policy reduces consumption and investment." Comment on thisstatement.A reduction in money supply raises interest rates, which will, in turn, have a negative effect on the level of investment spending. The level of consumption may also decrease as it becomes more costly to finance expenditures by borrowing money. But even if it is assumed that consumption is not affected by changes in the interest rate, consumption will still decrease since restrictive monetary policy will reduce national income and therefore private spending.4. "If government spending is increased, money demand will increase." Comment.A change in government spending directly affects the expenditure sector and therefore the IS-curve. But in an IS-LM framework, the money sector is also affected indirectly. An increase in the level of government spending will shift the IS-curve to the right, leading to an increase in income. But the increase in income will lead to an increase in money demand, so the interest rate will have to increase in order to lower the quantity of money demanded and to bring the money sector back into equilibrium. Overall no change in money demand can occur, since equilibrium in the money sector requires that m s = M/P = m d, that is, money supply has to be equal to money demand, and money supply is assumed to be fixed.5. "An increase in autonomous investment reduces the interest rate and therefore the moneysector will no longer be in equilibrium." Comment on this statement.An increase in autonomous investment shifts the IS-curve to the right. The increase in income leads to an increase in the demand for money, which means that interest rates increase. The increase in interest rates then reduces the quantity of money demanded again to bring the money market back to equilibrium.6. "A monetary expansion leaves the budget surplus unaffected." Comment on this statement. Expansionary monetary policy, that is, an increase in money supply, will lower interest rates (the LM-curve will shift to the right). Lower interest rates will lead to an increase in investment spending and the economy will therefore be stimulated. But a higher level of national income increases the government’s tax revenues and therefore the budget surplus will increase.7. "Restrictive monetary policy implies lower tax revenues and therefore to an increase in thebudget deficit." Comment on this statement.A decrease in money supply will shift the LM-curve to the left. This will lead to an increase in the interest rate, which will lead to a reduction in spending and thus national income. But as income decreases, so does income tax revenue. Therefore, the budget deficit will increase because of the change in its cyclical component.78. “If the demand for money becomes more sensitive to changes in income, then the LM-curvebecome s flatter.” Comment on this statement.Along the LM-curve, an increase in the interest rate is always associated with an increase in income. This means that an increase in money demand (due to an increase in income) has to be offset by a decrease in the quantity of money demanded (due to an increase in the interest rate) to keep the money sector in equilibrium. But if money demand becomes more income sensitive, a smaller change in income is required for any specific change in the interest rate to keep the money sector in equilibrium. Therefore, the LM-curve becomes steeper (and not flatter) as money demand becomes more sensitive to changes in income.9. “A decrease in the income tax rate will increase the demand for money, shifting the LM-curveto the righ t.” Comment on this statement.A decrease in the income tax rate (t) will increase the expenditure multiplier (α). But with a larger expenditure multiplier, any increase in investment spending due to a decrease in the interest rate will lead to a larger increase in income. Since fiscal policy affects the expenditure sector, the IS-curve (not the LM-curve) will shift. The IS-curve will become flatter and shift to the right. This will lead to a new equilibrium at a higher level of income (Y) and a higher interest rate (i). But money supply is fixed and the LM-curve remains unaffected by fiscal policy. Therefore, at the new equilibrium (the intersection of the new IS-curve with the old LM-curve) the demand for money will not have changed, since the money sector has to be in an equilibrium at m s = m d(i,Y).10. “If the demand for money becomes more insensitive to changes in the interest rate, equilibriumin the money sector will have to be restored mostly through changes in income. This implies a flat LM-curve.” Comment on this statement.Any increase in income will increase money demand and this will drive the interest rate up. Therefore, the quantity of money balances demanded will decline again until the money sector is back in equilibrium. But if money demand is very interest insensitive, then a larger increase in the interest rate is needed to reach a new equilibrium in the money sector. This means that the LM-curve is steep and not flat.11. Assume the following IS-LM model:Expenditure Sector Money SectorSp = C + I + G + NX M = 700C = 100 + (4/5)YD P = 2YD = Y - TA m d = (1/3)Y + 200 - 10iTA = (1/4)YI = 300 - 20iG = 120NX = -20(a) Derive the equilibrium values of consumption (C) and money demand (m d).(b) How much of investment (I) will be crowded out if the government increases its purchasesby ∆G = 160 and nominal money supply (M) remains unchanged?(c) By how much will the equilibrium level of income (Y) and the interest rate (i) change, ifnominal money supply is also increased to M' = 1,100?a. Sp = 100 + (4/5)[Y - (1/4)Y] + 300 - 20i + 120 - 20 = 500 + (4/5)(3/4)Y – 20i = 500 + (3/5)Y - 20iFrom Y = Sp ==> Y = 500 + (3/5)Y - 20i ==> (2/5)Y = 500 - 20i==> Y = (2.5)(500 - 20i) ==> Y = 1,250 - 50i IS-curveFrom M/P = m d ==> 700/2 = (1/3)Y + 200 - 10i ==> (1/3)Y = 150 + 10i==> Y = 3(150 + 10i) ==> Y = 450 + 30i LM-curve89IS = LM ==> 1,250 - 50i = 450 + 30i ==> 800 = 80i ==> i = 10==> Y = 1,250 - 50*10 ==> Y = 750C = 100 + (4/5)(3/4)750 = 100 + (3/5)750 ==> C = 550m s = M/P = 700/2 = 350 = m dCheck: m d = (1/3)750 + 200 - 10*10 = 350i25 IS o LM o10450 750 1,250 Yb. ∆IS = (2.5)160 = 400 ==> IS' = 1,650 - 50iIS' = LM ==> 1,650 - 50i = 450 + 30i ==> 1,200 = 80i ==> i = 15==> Y = 1,650 - 50*15 ==> Y = 900Since ∆i = + 5 ==> ∆I = - 20*5 ==> ∆I = - 100Check: ∆ 331510450 750 900 1,250 1,650 Yc. From M'/P = m d ==> 1,100/2 = (1/3)Y + 200 - 20i==> (1/3)Y = 350 - 20i ==> Y = 3(350 - 20i) ==> Y = 1,050 + 30iIS 1 = LM 1 ==> 1,650 - 50i = 1,050 + 30i ==> 600 = 80i ==> i = 7.5==> Y = 1,650 - 50(7.5) = 1,275.==> ∆i = - 7.5 and ∆Y = 375 as compared to (b).i1107.512. Assume the money sector can be described by these equations: M/P = 400 and m d = (1/4)Y - 10i.In the expenditure sector only investment spending (I) is affected by the interest rate (i), and the equation of the IS-curve is: Y = 2,000 - 40i.(a) If the size of the expenditure multiplier is α= 2, show the effect of an increase ingovernment purchases by ∆G = 200 on income and the interest rate.(b) Can you determine how much of investment is crowded out as a result of this increase ingovernment spending?(c)If the money demand equation were changed to m d = (1/4)Y, how would your answers in (a)and (b) change?a. From M/P = m d ==> 400 = (1/4)Y - 10i ==> Y = 1,600 + 40i LM-curveFrom IS = LM ==> 2,000 - 40i = 1,600 + 40i ==> 80i = 400 ==> i = 5==> Y = 2,000 - 40*5 ==> Y = 1,800∆IS = 2*200 = 400 ==> IS' = 2,400 - 40iIS' = LM ==> 2,400 - 40i = 1,600 + 40i ==> 80i = 800 ==> i = 10==> Y = 1,600 + 40*10 ==> Y = 2,000Therefore ∆i = + 5 and ∆Y = + 200b.Since the size of the expenditure multiplier is α = 2 but income only goes up by αY = 200, the fiscalpolicy multiplier in the IS-LM model is α1= 1. But this means that the level of investment has been reduced by 100, that is, ∆I = -100. This can be seen by restating the IS-curve as follows:Y = 2,000 - 40i = Y = 2(1,000 - 20i)Since government purchases are changed by ∆G = 200 ==> Y = 2(1,200 - 20i), which means that the IS-curve shifts by ∆IS = 2*200 = 400. But the increase in income is actually only ∆Y = 200. This implies that investment changes by ∆I = -100. Investment is of the form I = I o– 20i; however, since the interest rate went up by ∆i = 5, investment changes by ∆I = - 20*5 = - 100.From ∆Y = α(∆Sp) ==> 200 = 2(∆Sp) ==> ∆Sp = 100But since ∆Sp =∆ G + ∆I ==> 100 = 200 + ∆I ==> ∆I = - 100c. If m d= (1/4)Y, then we have the classical case, that is, a vertical LM-curve. In this case, fiscalexpansion will not change income at all. This occurs since the increase in G will be offset by a decrease in I of equal magnitude due to an increase in the interest rate.(M/P) = m d ==> 400 = (1/4)Y ==> Y = 1,600 LM-curveIS = LM ==> 2,000 - 40i = 1,600 ==> 40i = 400 ==> i = 10 ==> Y = 1,600IS' = LM ==> 2,400 - 40i = 1,600 ==> 40i = 800==> i = 20 ==> Y = 1,600 ==> ∆I = - 2001013. Assume money demand (md) and money supply (ms) are defined as: md = (1/4)Y + 400 - 15iand ms = 600, and intended spending is of the form: Sp = C + I + G + NX = 400 + (3/4)Y - 10i.Calculate the equilibrium levels of Y and i, and indicate by how much the Fed would have to change money supply to keep interest rates constant if the government increased its spending by ∆G = 50. Show your solutions graphically and mathematically.ms = md ==> 600 = (1/4)Y + 400 - 15i ==> (1/4)Y = 200 + 15i==> Y = 4(200 + 15i) ==> Y = 800 + 60i LM-curveY = C + I + G + NX ==> Y = 400 + (3/4)Y - 10i ==>(1/4)Y = 400 - 10i ==> Y = 4(400 - 10i) ==> Y = 1,600 - 40i IS-curveFrom IS = LM ==> 1,600 - 40i = 800 + 60i ==> 100i = 800 ==> i = 8 ==> Y = 1,280If government spending is increased by ∆G = 50, the IS-curve will shift to the right) by (∆IS) = 4*50 = 200. If the Fed wants to keep the interest rate constant, money supply has to be increased in a way that shifts the LM-curve to the right by exactly the same amount as the IS-curve, that is, (∆LM) = 200.From Y = 2(200 + 15i) ==> (∆Y) = 2(∆ms) ==> 200 = 2(∆ms)==> (∆ms) = 100, so money supply has to be increased by 100.Check: IS' = LM": 1,800 - 40i = 1,000 + 60i ==> 800 = 100i4018800 1000 1280 1480 1600 1800 Y14. Assume the equation for the IS-curve is Y = 1,200 – 40i, and the equation for the LM-curve isY = 400 + 40i.(a) Determine the equilibrium value of Y and i.(b) If this is a simple model without income taxes, by how much will these values change if thegovernment increases its expenditures by ∆G = 400, financed by an equal increase in lump sum taxes (∆TA o = 400)?a. From IS = LM ==> 1,200 - 40i = 400 + 40i ==>800 = 80i ==> i = 10 ==> Y = 400 + 40*10 ==> Y = 800b. According to the balanced budget theorem, the IS-curve will shift horizontally by the increase ingovernment purchases, that is, ∆IS = ∆G = ∆TA o = 400.Thus the new IS-curve is of the form: Y = 1,600 - 40i.From IS' = LM ==> 1,600 - 40i = 400 + 40i ==>1,200 = 80i ==> i = 15 ==> Y = 400 + 40*15 ==> Y = 1,00015. Assume you have the following information about a macro model:Expenditure sector: Money sector:11。
目 录第一部分 开篇导读及本书点评[1小时高清视频讲解]一、开篇导读二、本书点评及总结（结束语）第二部分 辅导讲义[31小时高清视频讲解]第1篇 导论与国民收入核算[视频讲解]第1章 导 论1.1 本章要点1.2 重难点解读第2章 国民收入核算2.1 本章要点2.2 重难点解读第2篇 增长、总供给与总需求，以及政策[视频讲解]第3章 增长与积累3.1 本章要点3.2 重难点解读第4章 增长与政策4.1 本章要点4.2 重难点解读第5章 总供给与总需求5.1 本章要点5.2 重难点解读第6章 总供给：工资、价格与失业6.1 本章要点6.2 重难点解读第7章 通货膨胀与失业的解剖7.1 本章要点7.2 重难点解读第8章 政策预览8.1 本章要点8.2 重难点解读第3篇 首要的几个模型[视频讲解]第9章 收入与支出9.1 本章要点9.2 重难点解读第10章 货币、利息与收入10.1 本章要点10.2 重难点解读第11章 货币政策与财政政策11.1 本章要点11.2 重难点解读第12章 国际联系12.1 本章要点12.2 重难点解读第4篇 行为的基础[视频讲解]第13章 消费与储蓄13.1 本章要点13.2 重难点解读第14章 投资支出14.1 本章要点14.2 重难点解读第15章 货币需求15.1 本章要点15.2 重难点解读第16章 联邦储备、货币与信用16.1 本章要点16.2 重难点解读第17章 政 策17.1 本章要点17.2 重难点解读第18章 金融市场与资产价格18.1 本章要点18.2 重难点解读第5篇 重大事件、国际调整和前沿课题[视频讲解]第19章 重大事件：萧条经济学、恶性通货膨胀和赤字19.1 本章要点19.2 重难点解读第20章 国际调整与相互依存20.1 本章要点20.2 重难点解读第21章 前沿课题21.1 本章要点21.2 重难点解读第三部分 名校考研真题名师精讲及点评[8小时高清视频讲解]一、名词解释二、简答题三、计算题四、论述题第一部分 开篇导读及本书点评[1小时高清视频讲解]一、开篇导读[0.5小时高清视频讲解]主讲老师：郑炳一、教材及教辅、课程、题库简介► 教材：多恩布什《宏观经济学》（第10版）（多恩布什、费希尔、斯塔兹著，王志伟译，中国人民大学出版社）► 教辅（两本，文库考研网主编，中国石化出版社出版）√网授精讲班【教材精讲+考研真题串讲】精讲教材章节内容，穿插经典考研真题，分析各章考点、重点和难点。
