what is the difference between a demand curve and a supply curve 
a demand curve represents the relationship between the price of a good or service and the quantity demanded for a given period of time typically as the price rises the demand falls as a result the curve slopes down from left to right a supply curve is a graphic representation of the correlation between the cost of a good or service and the quantity supplied for a given time period typically as the price of a product increases the quantity supplied also increases the resultant curve slopes upward from left to right 