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Marginal Revenue and Profit Recall that a revenue or profit function specifies the total revenue or profit as a function of the number of items x. The derivatives, and, of these functions are called the marginal revenue and marginal profit functions. They measure the rate of change of revenue and profit with respect to the number of items. Units The units of marginal revenue and profit are the same as those of marginal cost: dollar (euros, pesos, krona, marks, etc.) per item. Interpretation We interpret and as the approximate revenue and profit from the sale of one more item. 2) You operate an iPad refurbishing service. The cost to refurbish x IPads in a month is calculated to be: You charge customers $80 per iPad for the work. a) Calculate the marginal revenue and profit functions. b) Compute the revenue and profit, along with the marginal revenue and profit, if you have refurbished 20 units this month. c) For which value of x is the marginal profit zero? A: First calculate the revenue and profit functions. Perenue Eouston Proff Equation Now take the derivative of each to find the marginal revenue and profit functions: Marghai Revenue Equation Marginal Proth Equaton B: Because you've refurbished 20 IPads this month, C: The marginal profit is zero when