(4D) The demand and total cost functions of a good for a monopolist are given byP=-(1/1000)Q+500 and TC=400+20Q(I) Define the monopolist's profit function as a function of Q(ii) Derive and interpret the first-order condition for profit maximisation

Semester 2, 2020-2021 ECON4004 (iii) Solve for the values of O and P that maximise profit. 1 mark (vi) Verify the second-order condition. 2 marks (v) Show your results from (ii) and (iii) graphically. 3 marks