Prof. Nuwal was running behind today. Seem to be focusing on demand today.
The Law of Demand states that as price changes, demand is inversely affected, all else being equal. Demand is dependant on price. The reverse is not true. Price is independant of demand.
Demand is not merely interest in something. Demand requires strong desire, willingness to pay, and ability to pay.
Demand is affected by price and time. Price means the exchange value of the good or service; what would the demander be required to sacrifice? Time is shorthand for “circumstance”; as time passes, there is opportunity for circumstances to change.
A chart of prices to quantities demanded is called a demand schedule. A graph representing price on its Y-axis and quantity demanded on the x-axis demonstrates a demand curve. A demand curve is always high on its left side, and low on its left side.
The demand function is a mathematical representation of the same concept. D = f(P), where D is demand, and P is price.
Individual demand is the quantity of a good or service demanded by an individual consumer at some price or set of prices.
Market Demand is the sum quantities of a good or service demanded by all consumers at a price or set of prices. Also known as total demand.