vitÂ·riÂ·fy (vÄ­tâ²rÉ-fÄ«â²) v. vitÂ·riÂ·fied, vitÂ·riÂ·fyÂ·ing, vitÂ·riÂ·fies v.tr. To change or make into glass or a glassy substance, especially through heat fusion. v.intr. To become vitreous.
We draw a demand curve to show the relationship between the price of the good and the quantity that consumers are willing to buy. For example, suppose people are willing to buy 20 pounds of strawberries at a price of $2, but are willing to buy 30 pounds if the price falls to $1.
According to the law of demand, demand decreases as the price rises. In a perfectly competitive economy, the combination of the upward-sloping supply curve and the downward-sloping demand curve yields a supply and demand schedule that, at the intersection of the two curves, reveals the equilibrium price of an item. Theories of supply and demand had their roots in the early 20th cent.