CHAPTER 11 TEST B Directions: Show all work. Name: ______________________ Section: _____________________ 1. Which one of the following formulas could describe the graph below? a. 17 y x 2 1 d. y x2 4 x2 y2 1 b. 16 x2 y2 1 e. 16 x2 y 1 4 y2 x2 1 4 2 c. f. 2. Which one of the following equations represents a parabola with focus at 16,0 ? a. x d. x y2 4 b. x y2 4 e. x y2 16 y2 16 c. x f. x y2 64 y2 64 3. The ellipse with vertices at 3, 0 and 3, 16 , covertices at 6, 8 and 0, 8 is represented by which one of the following equations? a. 64 x 2 9 y 2 384 x 144 y 576 b. x 2 y 2 6 x 8 y 0 c. 8x 2 3 y 2 48x 24 y 24 d. 64 x 2 9 y 2 96 x 36 y 144 e. x 2 y 2 6 x 8 y 0 f. 8x 2 3 y 2 48x 24 y 24 4. Which one of the following equations represents a hyperbola centered at 1,1 , vertices at 0,1 , 2,1 and asymptotes y 1 2 x 1 ? a. x 1 2 4 d. x 1 2 y 1 1 2 y 1 4 Chapter 11/Form B b. 2 1 e. x 1 2 2 x 1 2 y 1 1 2 y 1 2 c. 2 1 f. y 1 2 y 1 2 x 1 2 1 4 2 x 1 1 2 5. Which one of the following shows the solution to the system of inequalities: 18 x 3 y 6 3 y 7 0 x6 a. b. c. d. 6. Information about the age distributions in three different villages (A, B and C) is given in the box plots shown below. Which one of the following statements about these trees below is not true? a. b. c. d. e. The youngest person lives in village C. Inhabitants of village A have the youngest median age. The median age of village A is greater than the first quartile age of village B. One quarter of people in village B are older than the oldest person in village A. One quarter of the inhabitants of village C are less than ten years of age. Chapter 11/Form B 7. Find the lengths of the major and minor axes and the coordinates of the foci for the x2 y 2 ellipse described by the equation 1 and sketch a graph for the ellipse 36 49 showing these features. 8. Find coordinates for the points on the ellipse x 4 48 2 y2 1 where x 2 . 9 9. Find the coordinates of the vertices and the equations for the asymptotes of x2 y2 1 and use these to sketch a graph of the hyperbola. 144 324 10. Find an equation for the parabola with a vertex at the origin and a focus at 0, 8 . Sketch a graph for the parabola showing these features together with the directrix. 11. Find an equation for the parabola with a vertex at 2,3 and a focus at 5,3 . Sketch a graph for the parabola showing these features together with the directrix. 12. Find the coordinates of the focus and an equation for the directrix of the parabola 2 described by x 3 y 2 1 . Sketch a graph for the parabola showing these features. 13. Find the center and the lengths of the major and minor axes of the ellipse described 1 1 by the equation x 2 9 y 2 x . Sketch a graph for the ellipse showing these 4 8 features. 14. Find the center, vertices and asymptotes for the hyperbola given by the equation 36 x 2 24 x 324 y 2 324 y 401 15. Find an equation for hyperbola shown below: Chapter 11/Form B Problems 16-20 refer to the linear programming problem in the following situation: The manager of a software retailer has asked her assistant for a cost analysis to help determine what software they will order. They are choosing between two types of database packages: Stackmaker, and a more expensive full-featured package called Deluxstack. The assistant must figure out how many packages of each software to order to minimize costs. It is required that they sell at least 300 packages (some combination of Stackmaker and Deluxstack.) A Stackmaker sale earns $18 in profit for the retailer, while a Deluxstack sale earns $24 in profit. Total profits on database software sales must be at least $6240. The wholesale cost of Stackmaker is $25. The wholesale cost Deluxstack is $40. The retailer buys software at the wholesale cost. 16. Let s represent the number of Stackmaker packages the retailer will order and let d represent the number of packages of Deluxstack the company will order. Write the constraints of the problem as inequalities in terms of s and d. 17. Write the objective function of the problem in terms of s and d. 18. Sketch the solution set to the constraint system. 19. Find the coordinates of the vertices of the solution set. 20. Find the combination of Stackmaker and Deluxstack packages that will minimize cost. What is this minimum cost? 21. Approximate to four significant digits the coordinates of the foci of the hyperbola given by x 3 2 2 y 4 2 2 6 2 . 2 22. The equation y 2 2 xy 2 x 2 1 can be solved for y using the quadratic formula. For a given x there may be two solutions: y x 3x 2 1. Graph these two functions on a calculator and describe what you see in terms of a conic section. 23. Approximate to 4 significant digits the value(s) of x in the solution(s) to the system: 2 x2 4 y 2 4 . 2 y 0.2 x 2 Chapter 11/Form B Problems 24 and 25 refer to the following linear programming problem: : x y maximize 2 1.4 3 1.7 3 2 y 5x 6 such that 7 2 2 y 3 x 10 24. Approximate to four significant digits the vertices of the solution region for the constraint system. Sketch a graph of the constraint system to show these. 25. Find the maximum value of constraint system. Chapter 11/Form B x y over the solution set of the 2 1.4 3 1.7 Solutions For Chapter 11 Test Form B. 1. b 2. f 3. a 4. d 5. b 6. d 7. The major axis has length 14 and the minor axis has length 12 while the foci are at 0, 13 . 8. 2 4 2 y2 y2 1 3 1 y 48 9 9 4 2 3 coordinates at 2, . 2 9. The vertices of the hyperbola are at 12,0 and the asymptotes are 3 x , as shown to the right: 2 x2 10. y is an equation for the parabola. 32 The graph is shown below: y 11. The equation for the parabola 1 2 is x 2 y 3 . The 28 directrix is x 9 . The graph is shown below to the right: Chapter 11/Form B 12. The vertex of x 3 y 2 1 is at 1, 2 and 2 the distance to the focus is p 1 so the focus 12 11 is at , 2 and the directrix is 12 A graph is shown at right: x 13 . 12 2 13. x 2 9 y 2 1 1 1 1 1 x x 9 y2 . 4 8 8 8 64 2 1 x 8 64 y 2 1 So the length of the 9 / 64 9 3 and the length 16 2 1 1 of the minor axis is 2a 2 . The 64 4 1 ellipse is centered at , 0 as shown: 8 2 2 14. 36 x 24 x 324 y 324 y 401 2 36 x 2 x 324 y 2 y 401 3 major axis is 2a 2 2 2 1 1 36 x 324 y 401 4 81 3 2 2 1 2 x 1 3 y 1 . So the center is 9 2 1 10 1 1 1 1 8 1 at , , the vertices are at 3, , and , and the asymptotes 2 3 2 3 2 3 3 2 1 1 1 1 7 11 1 and y x . are y x y x 2 3 3 3 18 18 3 y 2 2 x 3 2 1 , observe that the points 3, 1 and b2 a2 (0,0) are on the hyperbola so that b 1 and a 3 . Thus an equation for the 15. Starting with the form hyperbola is y 2 Chapter 11/Form B 2 x 3 3 2 1. s d 300 16. The constraint system is 18s 24d 6240 . s, d 0 17. The cost function, C 25s 40d , is to be minimized. 18. See sketch to the right: 19. As shown in the illustration, the vertices of 2 the solution set are 0,346 , 140,160 and 300, 0 . 3 2 20. The cost function is minimized at 0,346 where C = $ 8666.67 3 21. The foci are at 3 c, 4 where c 1 2 3 6 Thus the foci are near 5.568, 4 and 0.432, 4 . 22. These two functions comprise a hyperbola whose axes are tilted and whose center is near the origin, as shown at right. 23. Plotting the three functions involved and using the “ISECT” feature on the TI85 shows that there appears to be only one point of intersection near where x 1.769 24. As the screenshots at right show, the feasible region is a rhombus with vertices near 0.9107,0.1521 , 0.9915,0.1162 , 0.04898,1.170 , and 0.03185, 0.9016 . 25. Evidently, the maximum value of the object function is about 68.81 and is attained near 0.9107,0.1521 . Chapter 11/Form B 1 2 1 3 2.568