Marginal Cost: A division of Ditton Industries manufactures the Futura model microwave oven. The daily cost (in dollars) of producing these microwave ovens is 0.0002x^3 + 0.06x^2 + 120x + 5000, where x stands for the number of units produced. What is the actual cost incurred in manufacturing the 1st oven? The 2nd oven? The 3rd oven? b: What is the marginal cost when x = 100, 200, and 300?