Please do question 4 and 5

Question 4 [14] 4.1. Expiain why the P = MC rule is the same as the MR = MC rule for perfectly competitive firms but not for monopolists in the short run. (4) 4.2. Illustrate the MR = MC rule for a monOpoiy and show why, over the short run, it will always make economic profit. List at least one reason why economic prot is not necessarily always applicable over the long run. (10) Question 5 [5] Decide why the following statements are true or false and explain your decision. 5.1. A decision maker must always use the historical cost of raw materials in making an economic decision. (21/2) 5.2. The portion of the long-run average cost curve that is horizontal indicates that the firm is experiencing neither economies nor diseconomies of scale. (21/2)