Marginal cost A division of Ditton Industries manufactures the Futura model microwave oven. The daily cost (in dollars) of producing these microwave ovens is
$$
C(x)=0.0002 x^{3}-0.06 x^{2}+120 x+5000
$$
where $x$ stands for the number of units produced.
a. What is the actual cost incurred in manufacturing the 101 st oven? The 201 st oven? The 301 st oven?
b. What is the marginal cost when $x=100,200,$ and $300 ?$