In this problem you need to take a derivative in the form of marginal cost and undo the derivative to get the cost function. This is covered in Question 4 of Section13.1.
Solution To find the cost function C(x), we need to take the antiderivative of C ’(x):
To find K, we need to substitute 10 for x and set the result equal to 94.20:
Solve for K to get
This makes the cost function approximately