Assume that it costs a company approximately C(x) = 400,000 + 160x + 0.001x^2 dollars to manufacture x smartphones in an hour. (a) Find the marginal cost function. 160 + .002x Use it to estimate how fast the cost is increasing when x = 10,000. $ 180 per smartphone Compare this with the exact cost of producing the 10,001st smartphone. The cost is increasing at a rate of $ 180 per smartphone. The exact cost of producing the 10,001st smartphone is $ . Thus, there is a difference of $ . (b) Find the average cost function C and the average cost to produce the first 10,000 smartphones. C(x) = 400000/x + 160 + 0.001x C(10,000) = $ 210 (c) Using your answers to parts (a) and (b), determine whether the average cost is rising or falling at a production level of 10,000 smartphones. The marginal cost from (a) is lower than the average cost from (b). This means that the average cost is falling at a production level of 10,000 smartphones.