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3. If a firm enjoys economies of scale up to a certain output level, and cost then increases proportionately with output, what can you say about the shape of the long-run average cost curve? 4. A firm has a fixed production cost of $5000 and a constant marginal cost of production of $500 per unit produced What is the firm's total cost function? Average cost? b. if the firm wanted to minimize the average total cost, would it choose to be very large or very small? Explain