Question

Find the marginal profit
C(x) = 5x; R(x) = 9x − 0.001x^2

Answer 1

profit = R(x) - C(x)

marginal profit is derivative of profit
-the rate the profit is increasing at a given quantity

marginal profit = R'(x) - C'(x)

--> (9-.002x) - 5
--> 4 - .002x

Answer 2

side note:
max profit is achieved when marginal profit = 0