Plz plz help here.

Consider car makers that operate under monopolistic competition in symmetric equilibrium. Each monopolistic car maker produces with a total cost function TO =F+c.Qc, where F = 500, 000 and c = 100. Each of n car makers faces residual demand of of = S. - - b. (Pc-Pc) where S = 50, 000, b = 1/1000 and Po is average equilibrium price. 1. What are the average and marginal cost functions of a car maker? 2. What are marginal revenues? [Hint: Reformulate demand so that P = P(Q) ) and derive total revenue; differentiate total revenue with respect to quantity. ] 3. Graph the average-cost (CC) and the price (PP) schedules for this industry in a diagram that shows price, average cost and the number of firms (varieties) 4. Find the number of firms (varieties) in this industry in the absence of trade. What is price in a symmetric autarky equilibrium? 5. Cars can be traded across countries at not cost. Using the average-cost (CC) and the price (PP) schedules above, show how equilibrium price and the equilibrium number of firms change after trade. 6. How could you measure the gains from trade? Explain briefly