My AP Microeconomics teacher told us at the beginning of the semester that she is not a math person; it just became very evident that this is true. </p>
We are in the supply and demand unit and are covering how to calculate consumer surplus. In the example she drew the supply and demand curves and the market price at equilibrium. She then shaded in the triangle that represents the consumer surplus. </p>
She then proceeded to lecture us on how calculating the area will almost always yield the wrong answer in Econ. This seems strange to me–AP Econ websites, the textbook, and my prep book all say that consumer surplus is equal to the area of the triangle formed by the price axis, the demand curve, and the market price. Her answer for the area seemed completely incorrect, as she used a variant of a trapezoidal Riemann sum, so I tried to ask her about it privately. My AP Calc teacher was in there too, by chance, and happened to agree with me that something was wrong. However, she still says that consumer surplus is not area. </p>
Is she right? All other reputable sites say area will work for calculating consumer surplus, and I don’t want to learn such a crucial topic incorrectly. I feel like the answer should be the triangle’s area… Arg! Help?</p>
(If desired, I have a link to the problem in question.)</p>