Problem Set C (1) Find and classify the extreme values of 4 6 ( ) 6 4f x x x over the interval [ 2, 2]. (2) A retailer determines that the cost of ordering and storing units of a product can be modelled by by 20000( ) 3 ,C x x x 0 200.x Find the order size that will minimise ordering and storage cost. (3) The demand curve of a firm is 1200 21p q and its total cost is 3 2 ( ) 2 66 600 1000C q q q q where q is the output of the firm (in thousands).4 (i) Derive an expression ( ) R q for the firm' s revenue function. (ii) Derive an expression ( ) qfor the firm' s profit function. (iii) Is the rate of change of profit increasing or decreasing when the output level of the firm is 10,000 units? (iv) Determine the level of output at which profit is maximized.