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.
Demand curves generally have a negative gradient indicating the inverse relationship between quantity demanded and price. There are at least three accepted explanations of why demand curves slope downwards: The law of diminishing marginal utility. The income effect.