EM C2 demand, supply, and equilibrium prices

demand - - -- the functional relationship between the price of a good or service and the quantity demanded by consumers in a given period of time, all else held constant (consumer behavior)

supply - -- - - the functional relationship between the price of a good or service and the quantity supplied by producer in a given period of time, all else held constant ( producer behavior)

functional relationship
a relationship between variables, usually expressed in an equation using symbols for variables, where the value of one variable, the independent variable, determines the value of the other, the dependent variable

nonprice factors influencing demand
tastes and preferences
income
for of which the demand varies directly with income, it\'s called a normal good
if the demand varies inversely with income, the good is termed an inferior good

prices of related goods
substitute goods
two goods, X and Y, are substitutes if an increase in the price of good Y causes consumers to increase their demand for good X or if a decrease in the price of good Y causes consumers to decrease their demand for good X

complementary goods
two goods, X and Y, are complementary if an increase in the price of good Y causes consumers to decrease their demand for good X or if a decrease in the price of good Y causes consumers to increase their demand for good X

future expectations

number of consumers

demand function
individual demand function
the function that shows, in symbolic or mathematical terms, the variables that influence the quantity demanded of a particular product by an individual consumer

market demand function
the function that shows, in symbolic or mathematical terms, the variables that influence the quantity demanded of a particular product by all consumers in the market and that is thus affected by the number of consumers in the market

demand curve
the graphical relationship between the price of a good and the quantity consumers demand, with all other factors influencing demand held constant

demand shifters
the variables in a demand function that are held constant when defining a given demand curve, but that would shift the demand curve if their values changed

negative(inverse) relationship
a relationship between two variables, graphed as a downward sloping line, where an increase in the value of one variable causes a decrease in the value of the other variable

change in quantity demanded and change in demand