IMPORTANT FORMULAS AND CONDITIONS


Chapter 5

1.   Optimal decision making: MB = MC

2.   Opportunity cost from a production possibility curve or frontier (PPC or PPF):

       Good X: The slope of the PPC

       Good Y: The inverse of the slope of the PPC

Chapter 6

1.   Market equilibrium:

       Q d = Q s

2.   Shortage:

       Q dQ s

3.   Surplus:

       Q sQ d

4.   Total welfare:

       = Consumer surplus + Producer surplus

Chapter 7

   1. Nominal GDP:

       = Current year production × Current year prices

   2. Real GDP:

       Images

   3. Aggregate spending (GDP):

       = C + I + G + (XM )

   4.   Disposable income (DI):

       = Gross income – Net taxes

   5. Net taxes:

       = Taxes paid – Transfers received

   6. %Δ real GDP:

       = %Δ nominal GDP – %Δ price index

   7. Price index current year:

       = 100 × (Spending current year)/(Spending base year)

   8. Consumer inflation rate:

       = 100 × (CPINew – CPIOld )/CPIOld

   9. Real Income:

       = (Nominal income)/CPI (in hundredths)

10. Nominal interest rate:

       = Real interest rate + Expected inflation

11. Labor force:

       = Employed + Unemployed

12. Unemployment rate:

       = 100 × (Unemployed/Labor force)

Chapter 8

   1. Consumption function:

       C = Autonomous consumption + MPC(DI)

   2. Saving function:

       S = Autonomous savings + MPS(DI)

   3. Marginal propensity to consume (MPC):

       = ΔC /ΔDI = Slope of consumption function

   4. Marginal propensity to save (MPS):

       = ΔSDI = Slope of saving function

   5. MPC + MPS = 1

   6. Net exports (XM ):

       = Exports – Imports

   7. Equilibrium in the loanable funds market:

       S = I

   8. Spending multiplier:

       = 1/(1 – MPC) = 1/MPS

       = (Δ GDP)/(Δ spending)

   9. Tax multiplier (Tm):

       = MPC × (Spending multiplier) = MPC/MPS

       = (Δ GDP)/(Δ taxes)

10. Balanced-budget multiplier = 1

Chapter 9

   1. Macroeconomic short-run equilibrium

       AD = SRAS

   2. Macroeconomic long-run equilibrium

       AD = SRAS = LRAS

   3. Recessionary gap:

       = Full employment GDP – Current GDP

   4. Inflationary gap:

       = Current GDP – Full employment GDP

Chapter 10

   1. Budget deficit:

       = Government spending – Net taxes

   2. Budget Surplus:

       = Net taxes – Government spending

Chapter 11

1.   M 1 measure of money:

       = Cash + Coins + Checking Deposits + Traveler’s checks

2.   M 2 measure of money:

       = M 1 + Savings deposits + Small (e.g., under $100,000 CDs) time deposits + Money market deposits + Money market mutual funds

3.   Present value (PV) of $1 received a year from today:

       = $1/(1 + r )

4.   Future Value (FV) of $1 invested today at interest rate r for one year = $1 × (1 + r )

5.   Money demand:

       = Transaction demand + Asset demand

6.   Equilibrium in the money market:

       MS = MD

7.   Reserve ratio (rr )

       = Required reserves/Total deposits

8.   Simple money multiplier:

       = 1/rr

Chapter 12

1.   Equilibrium in the currency ($) market:

       Q d for the $ = Q s of the $

2.   Revenue from a tariff:

       = Per unit tariff × Units imported