Introduction to Microeconomics: Supply, Demand, and Price Elasticity

Forces of Supply and DemandPage 1

Supply and demand are the fundamental forces of market economies. They determine the price of goods and services, guiding the allocation of limited resources. The supply and demand model, despite its simplified assumptions, is an essential tool for understanding complex economic phenomena like inflation, unemployment, and taxation.

Market Competition and AssumptionsPage 2

A perfectly competitive market consists of so many buyers and sellers that no single individual can influence the price. Key assumptions for a competitive market include many participants, perfect information, freedom of entry/exit, and clearly defined property rights.

The Law of DemandPage 3

The law of demand states that, all else being equal, the quantity demanded of a good decreases as its price increases. This relationship is illustrated by the downward-sloping demand curve, driven by income and substitution effects.

Shifts in Demand vs. Movement Along the CurvePage 5

A movement along the demand curve occurs when the price of the good itself changes. A shift of the entire curve occurs due to external factors like changes in income, prices of related goods (substitutes/complements), consumer tastes, or market size.

The Law of SupplyPage 6

The law of supply states that, all else being equal, the quantity supplied of a good increases as its price increases. The supply curve slopes upward, reflecting producers' incentives to increase output at higher prices.

Market EquilibriumPage 8

Equilibrium is reached at the price where the quantity demanded equals the quantity supplied. If prices are above or below this point, surpluses (excess supply) or shortages (excess demand) arise, triggering automatic market adjustments back to equilibrium.

Price as an Information SignalPage 9

Prices on a free market serve as information signals. High prices signal scarcity and incentivize production, while low prices signal surplus and encourage a reduction in output, coordinating independent decisions without central planning.

Analyzing Equilibrium ChangesPage 10

Changes in market conditions are analyzed using a three-step process: identifying which curve shifts, the direction of the shift, and the resulting impact on equilibrium price and quantity.

Price ElasticityPage 11

Price elasticity measures the sensitivity of quantity (demanded or supplied) to changes in price. Demand elasticity is influenced by the availability of substitutes, whether the good is a necessity or luxury, and the time horizon.

Elasticity and Total RevenuePage 13

The relationship between price changes and total revenue depends on elasticity. If demand is inelastic, a price decrease reduces total revenue; if elastic, a price decrease increases total revenue.