The cost of producing x ounces of silver from a silver mine is c = f(x) dollars. a) What does the derivative of f(x) mean? Is the derivative the instantaneous cost? Is f(x) the average cost to get silver out of the ground or the change in cost over change in ounces? b) What does the statement f ' (600) = 25 mean? Does this mean that plugging in a x value 600 yields a y value (amount of instantaneous dollars) of 25? c) Do you think f ' (x) will increase/decrease in short run? Long run? Explain. I just would say if we go back to silver standard, it would decrease (economies of scale) in both long run and short run.