Final answer:
The marginal cost of producing the 10th item is 2 dollars.
Step-by-step explanation:
The marginal cost of producing the 10th item can be found by calculating the change in total cost divided by the change in quantity. In this case, the change in quantity is 10 - 9 = 1. The change in total cost is C(10) - C(9) = (1000 + 2(10^2)) - (1000 + 2(9^2)) = 1000 + 20 - 1000 - 18 = 2. Therefore, the marginal cost of producing the 10th item is 2 dollars.