The cost function for q units of a certain item is C(q)equals109 q plus 90. The revenue function for the same item is R(q)equals109 q plus StartFraction 45 q Over ln q EndFraction . a. Find the marginal cost. b. Find the profit function. c. Find the profit from one more unit sold when 8 units are sold.

a) $109

b)

c)

Step-by-step explanation:

a) The marginal cost, or the cost per additional unit, is given by the derivate of the cost function:

b) Profit is given by Revenue minus Cost:

c) The marginal profit for 8 units, is given by the difference in profit for 9 units and 8 units:

7.25

step-by-step explanation:

we know that 7 equals to 7.0. we also know that 1/4=0.25. so we can add the two together and we get 7.25