4. Consider a linear inverse demand function: 1) = a qu, (where CL, b > 0). a. What is consumer surplus, in terms of price? b. Show that, in the case of linear demand (although it is also true in general), the marginal effect on consumer surplus of a change in price is dCS _ _ dP _ q. c. Show that, in the case of linear demand, for a nonderivative-sized changes in prices (say from p1 to p2), ACS _ _A AP q, where a is the average of the demands at p1 and p2