How do you find the slope of a demand curve?

Question

William Abdalla · Accepted Answer

The slope of a demand curve can be found just like the slope of any other line. Remember, in order to find a slope, you must divide rise by run. In the case of a demand curve, this means dividing change in price by change in quantity demanded. Mathematically, this looks like  #(P_"2"-P_"1")/(Q_"2"-Q_"1")#  Note that in order to calculate this slope, you need two points that you know are on the demand curve. The ordered pairs of course being  #(Q_"1",P_"1") and (Q_"2",P_2)#. Remember that this works ONLY when the demand curve is linear. If you are taking a calculus based economics course, the slope is the derivative at the specific quantity value. If you have not learned learned derivatives yet, I will extend my answer.

Luke Alvarez · Answer

undefined To find the slope of a demand curve, you need two points on the curve. The slope represents the change in quantity demanded divided by the change in price. So, choose two points (P1, Q1) and (P2, Q2) on the demand curve. Then, calculate the change in quantity demanded (ΔQ) and the change in price (ΔP). Finally, divide the change in quantity demanded by the change in price to find the slope: slope = ΔQ / ΔP.