Recall from the previous chapter that the consumers’ surplus is defined by

where D(q) is the demand function, q₀ is the equilibrium quantity, and p₀ = D(q₀) is the equilibrium price. Find the consumers’ surplus for each of the following demand functions and equilibrium quantities.

D(q) = (q + 20)e^-0.1q, q₀ = 10

90 [D(q) - poldq,