1. Markets, Demand, and Supply
A market is an institution in which buyers and sellers exchange goods and services for a medium of exchange --money

2. What is demand?
Definitions:
Demand: The quantity of a good or service buyers are willing (and able) to buy at alternative market prices, ceteris paribus.
Quantity demanded: The quantity of a good or service buyers are willing (and able) to buy at a specific price, ceteris paribus.
Demand curve: The schedule indicating the quantities demanded of a good or service at alternative market prices, ceteris paribus.
Law of demand: ceteris paribus, price and quantity demanded of a good or service are negatively related

3. The demand for pineapple
The demand for pineapple depends on:
The price of pineapple
The price of canteloupe
Consumer income
Consumer tastes
As we move along the demand curve for, all factors are held constant except the price of pineapple

4. Here we derive the market demand curve by summing up the individual demand curves for pineapple

5. Deriving the demand for canteloupe
Price ($)
Anita
2.50 BO
2.00
1.50
Market demand
1.00 3 4 6 7 10 12
Quantity

6. Shifts of the demand curve
Demand could shift right due to:
Increase in the price of substitutes
Decrease in the price of complements
Increase in income
Change of tastes and preferences
Price H A P2 P1 B D2 D1 q1 q2
Quantity

7. Shifts of the demand curve, part II
Demand could shift left due to:
Decrease in the price of substitutes
Increase in the price of complements
Decrease in income
Change of tastes and preferences
Price H A P2 P1 B D1 D0 q1 q2
Quantity