In the above problems, you developed cost, revenue, and pro t functions that were dependent on time. However, in business and economics, it is important to have the cost, revenue, and pro t functions depend on units of product produced, which in this problem, is pounds of apples per tree. Write down cost, revenue, and pro t functions that are now functions of pounds of apples per tree. (a) Find the marginal cost, revenue, and pro t functions. In terms of pounds of apples, carefully explain what useful information can be gathered from marginal functions (b) Use Matlab to determine when your marginal pro t function is 0. Also use Matlab to graph your marginal pro t function. (c) Using the information in (b.), write down the interval(s) where your marginal pro t function is positive and where it is negative. How do you interpret a positive marginal pro t function? I negative marginal pro t function? (d) How many pounds of apples per tree is optimal