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4.(a) The demand function for a firm's product is q=150,000-75p where q equals the number of units demanded and p equals the price in dollars. (i) Determine the price which should be charged to maximize total revenue. (ii )what is maximum value for total revenue? (iii)how many units are expected to be demanded? (b) The total cost and total revenue functions for a product are C(q) = 500 + 100q + 0.5q2 R(q) = 500q (i) using the marginal approach, determine the profit-maximizing level of output. what is maximum profit? (c) Suppose that the demand equation for a monopolist is p=100-0.01x and the cost function is C(x)=50x +10,000. Find the value of x that maximizes the profit and determine the corresponding price and total profit for this level of production