MA 116 Turn-in Practice Problems 4.2 and 4.4 Pitts Name ___________________________ 1. (4.4 # 4) The price p, in dollars, and the quantity x sold of a certain product obey the demand equation 1 100 3 p x a.) Express the revenue R as a function of x. Show your work. c.) What is the revenue if 100 units are sold? d.) What quantity x maximizes the revenue? What is the maximum revenue? Show your algebra. You may use 2 b x a . Quantity x = ______________ Maximum revenue ______________ e.) What price should the company charge to maximize revenue? 2. (4.4 # 6) The price p (in dollars) and the quantity x sold of a certain product obey the demand equation 20 500 0 p 25x p . a.) Solve for p in terms of x. That is write p as a function of x. b.) Express the revenue R as a function of x. Show your work c.) What quantity x maximizes the revenue? What is the maximum revenue? Show your algebra. Y Quantity x = ______________ Maximum revenue ______________ d.) What price should the company charge to maximize revenue? 3. (4.4 # 8). Beth has 3000 feet of fencing to enclose a rectangular field. (Show algebra) a.) Express the area A of the rectangle as a function of x, where x is the length of the rectangle. b.) For what value of x is the area largest? Show algebra. c.) What is the maximum area? 3. (4.4 # 10). A farmer with 2000 meters of fencing wants to enclose a rectangular plot that borders on a straight highway, so he won’t fence the side along the highway. Express the area A of the rectangle as a function of x. highway x y For what value of x is the area a maximum? Show algebra. What is the maximum area? 5. (4.4 # 26). A shot-putter throws a ball at an inclination of 45o to the horizontal. The following data represents the height of the ball h feet at the instant that it has traveled x feet horizontally. Distance x 20 40 60 80 100 120 140 160 180 200 Height h 25 40 55 65 71 77 77 75 71 64 b.) Using your graphing calcualtor find the quadratic function of best fit that models the relation between distance and height. Record your answer rounded to four decimal places, but in your calculator store all the decimals. H(x) = _______________________________ c.) Use the function stored in your calculator to determine how far the ball will travel before it reaches its maximum height. Round to the nearest integer. d.) What is that maximum height? Round to the nearest integer. 6. See 4.2 # 22 c and g) A marketing firm wishes to find a function that relates the sales S of a product and A, the amount spent on advertising the product. The data are obtained from past experience. Advertising and sales are measure in thousands of dollars. Use your graphing calculator; find the line of best fit relating advertising expenditure ...