2. 4 - 1 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show Consumer Behavior and Utility Maximization 4 LECTURE

3. 4 - 2 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show LAW OF DIMINISHING MARGINAL UTILITY Utility Defined Subjective Nature Difficult to Quantify Total Utility Marginal Utility graphically examined...

4. 4 - 3 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show TOTAL AND MARGINAL UTILITY Tacos consumed per meal Total Utility, Utils Marginal Utility, Utils 0101 0 10 Units consumed per meal 30 20 10 Total Utility (utils) Marginal Utility (utils) 10 8 6 4 2 0 -2 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7

5. 4 - 4 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show TOTAL AND MARGINAL UTILITY Tacos consumed per meal Total Utility, Utils Marginal Utility, Utils 0101 0 10 Units consumed per meal 30 20 10 Total Utility (utils) Marginal Utility (utils) 10 8 6 4 2 0 -2 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7

6. 4 - 5 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show TOTAL AND MARGINAL UTILITY Tacos consumed per meal Total Utility, Utils Marginal Utility, Utils 012012 0 10 18 10 8 Units consumed per meal 30 20 10 Total Utility (utils) Marginal Utility (utils) 10 8 6 4 2 0 -2 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7

7. 4 - 6 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show TOTAL AND MARGINAL UTILITY Tacos consumed per meal Total Utility, Utils Marginal Utility, Utils 01230123 0 10 18 24 10 8 6 0 1 2 3 4 5 6 7 Units consumed per meal 30 20 10 Total Utility (utils) Marginal Utility (utils) 10 8 6 4 2 0 -2 1 2 3 4 5 6 7

8. 4 - 7 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show TOTAL AND MARGINAL UTILITY Tacos consumed per meal Total Utility, Utils Marginal Utility, Utils 0123401234 0 10 18 24 28 10 8 6 4 Units consumed per meal 30 20 10 Total Utility (utils) Marginal Utility (utils) 10 8 6 4 2 0 -2 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7

9. 4 - 8 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show TOTAL AND MARGINAL UTILITY Tacos consumed per meal Total Utility, Utils Marginal Utility, Utils 012345012345 0 10 18 24 28 30 10 8 6 4 2 Units consumed per meal 30 20 10 Total Utility (utils) Marginal Utility (utils) 10 8 6 4 2 0 -2 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7

10. 4 - 9 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show TOTAL AND MARGINAL UTILITY Tacos consumed per meal Total Utility, Utils Marginal Utility, Utils 01234560123456 0 10 18 24 28 30 10 8 6 4 2 0 Units consumed per meal 30 20 10 Total Utility (utils) Marginal Utility (utils) 10 8 6 4 2 0 -2 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7

11. 4 - 10 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show TOTAL AND MARGINAL UTILITY Tacos consumed per meal Total Utility, Utils Marginal Utility, Utils 0123456701234567 0 10 18 24 28 30 28 10 8 6 4 2 0 -2 Units consumed per meal 30 20 10 Total Utility (utils) Marginal Utility (utils) 10 8 6 4 2 0 -2 TU MU 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7

12. 4 - 11 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show TOTAL AND MARGINAL UTILITY Tacos consumed per meal Total Utility, Utils Marginal Utility, Utils 0123456701234567 0 10 18 24 28 30 28 10 8 6 4 2 0 -2 Units consumed per meal 30 20 10 Total Utility (utils) Marginal Utility (utils) 10 8 6 4 2 0 -2 TU MU 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 Observe Diminishing Marginal Utility

13. 4 - 12 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show THEORY OF CONSUMER BEHAVIOR A Typical Consumer... Exhibits Rational Behavior Has Clear-Cut Preferences Subject to a Budget Constraint Responds to Price Changes

14. 4 - 13 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show THEORY OF CONSUMER BEHAVIOR Utility Maximizing Rule The consumer’s money income should be allocated so that the last dollar spent on each product yields the same amount of extra (marginal) utility illustrated...

15. 4 - 14 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION How should the $10 Income be allocated?

16. 4 - 15 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION Examine the two marginal utilities

17. 4 - 16 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION Examine the two marginal utilities …per dollar

18. 4 - 17 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION Decision: Buy 1 Product B for $2

19. 4 - 18 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Second 8 8 20 10 Third 7 7 18 9 Fourth 6 6 16 8 Fifth 5 5 12 6 Sixth 4 4 6 3 Seventh 3 3 4 2 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION What next?

20. 4 - 19 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Second 8 8 20 10 Third 7 7 18 9 Fourth 6 6 16 8 Fifth 5 5 12 6 Sixth 4 4 6 3 Seventh 3 3 4 2 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION What next? Buy one of each

21. 4 - 20 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Second 8 8 20 10 Third 7 7 18 9 Fourth 6 6 16 8 Fifth 5 5 12 6 Sixth 4 4 6 3 Seventh 3 3 4 2 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION and then... ($5 left)

22. 4 - 21 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Second 8 8 20 10 Third 7 7 18 9 Fourth 6 6 16 8 Fifth 5 5 12 6 Sixth 4 4 6 3 Seventh 3 3 4 2 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION third unit of product B

23. 4 - 22 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Second 8 8 20 10 Third 7 7 18 9 Fourth 6 6 16 8 Fifth 5 5 12 6 Sixth 4 4 6 3 Seventh 3 3 4 2 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION $3 left...

24. 4 - 23 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Second 8 8 20 10 Third 7 7 18 9 Fourth 6 6 16 8 Fifth 5 5 12 6 Sixth 4 4 6 3 Seventh 3 3 4 2 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION $3 left... Buy both!

25. 4 - 24 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show First 10 10 24 12 Second 8 8 20 10 Third 7 7 18 9 Fourth 6 6 16 8 Fifth 5 5 12 6 Sixth 4 4 6 3 Seventh 3 3 4 2 Unit of product $ 10 income Product A: Price = $1 Product B: Price = $2 Marginal utility, utils Marginal utility per dollar (MU/price) Marginal utility, utils Marginal utility per dollar (MU/price) UTILITY MAXIMIZING COMBINATION Income is gone... the last dollar spent on each good gave the same utility (8) per dollar

26. 4 - 25 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show Algebraic Restatement of the Utility Maximization Rule MU of product A Price of A MU of product B Price of B = UTILITY MAXIMIZING COMBINATION

27. 4 - 26 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show UTILITY MAXIMIZATION AND THE DEMAND CURVE Create a demand schedule from the purchase decisions as the price of the product is varied... Price per unit of B Quantity Demanded $24 16 Graphically… Deriving the Demand Schedule and Curve

28. 4 - 27 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show UTILITY MAXIMIZATION AND THE DEMAND CURVE Deriving the Demand Schedule and Curve Quantity Demanded of Good B Price per unit of Good B $2 1 0 4 6 DBDB

29. 4 - 28 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show Indifference Curve Analysis 4 LECTURE APPENDIX

30. 4 - 29 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show A CONSUMER’S PRODUCT INDIFFERENCE Quantity of A Quantity of B 12 10 8 6 4 2 0 2 4 6 8 10 12 Units of A Price $1.50 Units of B Price $1.00 Total Expenditures 8 0 $12 6 3 12 4 6 12 2 9 12 0 12 12 An Indifference Schedule Combi- nation Units of A Units of B j 12 2 k 6 4 l 4 6 m 3 8 j k l m I

31. 4 - 30 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show A CONSUMER’S BUDGET LINE Units of A Price $1.50 Units of B Price $1.00 Total Expenditures 8 0 $12 6 3 12 4 6 12 2 9 12 0 12 12 (Attainable) Quantity of A Quantity of B 12 10 8 6 4 2 0 2 4 6 8 10 12 (Unattainable)

32. 4 - 31 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show A CONSUMER’S BUDGET LINE Units of A Price $1.50 Units of B Price $1.00 Total Expenditures 8 0 $12 6 3 12 4 6 12 2 9 12 0 12 12 (Attainable) Quantity of A Quantity of B 12 10 8 6 4 2 0 2 4 6 8 10 12 (Unattainable) An Increase in income makes the purchase of more of either or both items possible

33. 4 - 32 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show A CONSUMER’S BUDGET LINE Units of A Price $1.50 Units of B Price $1.00 Total Expenditures 8 0 $12 6 3 12 4 6 12 2 9 12 0 12 12 (Attainable) Quantity of A Quantity of B 12 10 8 6 4 2 0 2 4 6 8 10 12 (Unattainable) Price changes cause a change in the quantity demanded of the items

34. 4 - 33 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show A CONSUMER’S EQUILIBRIUM POSITION I1I1 I2I2 Quantity of A Quantity of B 12 10 8 6 4 2 0 2 4 6 8 10 12 I3I3 I4I4 (Attainable) (Unattainable) Units of A Price $1.50 Units of B Price $1.00 Total Expenditures 8 0 $12 6 3 12 4 6 12 2 9 12 0 12 12 An Indifference Schedule Combi- nation Units of A Units of B j 12 2 k 6 4 l 4 6 m 3 8

35. 4 - 34 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show What happens if the price of B increases to $1.50 Price B Quantity B $1.006 A CONSUMER’S EQUILIBRIUM POSITION I3I3 The budget line rotates reflecting the reduction in the quantity of B units which is attainable Quantity of A Quantity of B 12 10 8 6 4 2 0 2 4 6 8 10 12

36. 4 - 35 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show What happens if the price of B increases to $1.50 Price B Quantity B $1.00 1.50 6363 By recording the various quantities demanded at the various prices yields the Demand schedule A CONSUMER’S EQUILIBRIUM POSITION I2I2 I3I3 The budget line rotates reflecting the reduction in the quantity of B units which is attainable Quantity of A Quantity of B 12 10 8 6 4 2 0 2 4 6 8 10 12

37. 4 - 36 Copyright McGraw-Hill/Irwin, 2002 The Law of Demand Law of Diminishing Marginal Utility Total and Marginal Utility Theory of Consumer Behavior Utility Maximizing Combination Utility Maximization and the Demand Curve Applications and Extensions Key Terms Previous Slide Next Slide End Show What happens if the price of B increases to $1.50 Price B Quantity B $1.00 1.50 6363 By recording the various quantities demanded at the various prices yields the Demand schedule A CONSUMER’S EQUILIBRIUM POSITION Price of B Quantity of B $1.50 1.00 0 2 4 6 8 10 12 DBDB Plotting the Points yields the Demand Curve for Product B