a. If unlimited funds are available, how much should the manufacturer in Exercise 22 spend on development and how much on promotion to generate the largest possible profit?

b. Suppose the allocation problem in part (a) is solved by the method of Lagrange multipliers. What is the value of l that corresponds to the optimal budget? Interpret your answer in terms of dM/dk.

c. Your answer to part (b) should suggest another method for solving the problem in part (a). Solve the problem using this new method.