Law of Demand

1. Law of Demand • A decrease in the price of a good, all other things held constant, will cause an increase in the quantity demanded of the good. • An increase in the price of a good, all other things held constant, will cause a decrease in the quantity demanded of the good.

2. Change in Quantity Demanded Price An increase in price causes a decrease in quantity demanded. P1 P0 Quantity Q1 Q0

3. Change in Quantity Demanded Price A decrease in price causes an increase in quantity demanded. P0 P1 Quantity Q0 Q1

4. Changes in Demand • Change in Buyers’ Tastes • Change in Buyers Incomes • Normal Goods • Inferior Goods • Change in the Number of Buyers • Change in the Price of Related Goods • Substitute Goods • Complementary Goods

5. Change in Demand An increase in demand refers to a rightward shift in the market demand curve. Price P0 Quantity Q0 Q1

6. Change in Demand A decrease in demand refers to a leftward shift in the market demand curve. Price P0 Quantity Q1 Q0

7. Law of Supply • A decrease in the price of a good, all other things held constant, will cause a decrease in the quantity supplied of the good. • An increase in the price of a good, all other things held constant, will cause an increase in the quantity supplied of the good.

8. Change in Quantity Supplied A decrease in price causes a decrease in quantity supplied. Price P0 P1 Quantity Q1 Q0

9. Change in Quantity Supplied An increase in price causes an increase in quantity supplied. Price P1 P0 Quantity Q0 Q1

10. Changes in Supply • Change in Production Technology • Change in Input Prices • Change in the Number of Sellers

11. Change in Supply An increase in supply refers to a rightward shift in the market supply curve. Price P0 Quantity Q0 Q1

12. Change in Supply A decrease in supply refers to a leftward shift in the market supply curve. Price P0 Quantity Q1 Q0

13. Market Equilibrium • Market equilibrium is determined at the intersection of the market demand curve and the market supply curve. • The equilibrium price causes quantity demanded to be equal to quantity supplied.

14. Market Equilibrium Price D S P Quantity Q

15. D1 P1 Q1 Market Equilibrium Price D0 S0 An increase in demand will cause the market equilibrium price and quantity to increase. P0 Quantity Q0

16. D1 P0 P1 Q1 Q0 Market Equilibrium Price D0 S0 A decrease in demand will cause the market equilibrium price and quantity to decrease. Quantity

17. S0 S1 P1 Q1 Market Equilibrium Price An increase in supply will cause the market equilibrium price to decrease and quantity to increase. D0 P0 Quantity Q0

18. S1 S0 P1 P0 Q1 Q0 Market Equilibrium Price A decrease in supply will cause the market equilibrium price to increase and quantity to decrease. D0 Quantity

19. Concept of the Derivative The derivative of Y with respect to X is equal to the limit of the ratio Y/X as X approaches zero.

20. Rules of Differentiation Constant Function Rule: The derivative of a constant, Y = f(X) = a, is zero for all values of a (the constant).

21. Rules of Differentiation Power Function Rule: The derivative of a power function, where a and b are constants, is defined as follows.

22. Rules of Differentiation Sum-and-Differences Rule: The derivative of the sum or difference of two functions U and V, is defined as follows.

23. Rules of Differentiation Product Rule: The derivative of the product of two functions U and V, is defined as follows.

24. Rules of Differentiation Quotient Rule: The derivative of the ratio of two functions U and V, is defined as follows.

25. Rules of Differentiation Chain Rule: The derivative of a function that is a function of X is defined as follows.

26. Optimization With Calculus Find X such that dY/dX = 0 Second derivative rules: If d2Y/dX2 > 0, then X is a minimum. If d2Y/dX2 < 0, then X is a maximum.