Suppose that the cost, in dollars, for a company to produce $x$ pairs of a new line of jeans is $$C(x)=2400 +6 x+0.01 x^2+0.0002 x^3.$$
(a) Find the marginal cost function.
Answer:

(b) Find the marginal cost at $x=100$.
Answer:

(c) Find the cost at $x=100$.
Answer: