increases is a decreasing function. SOLUTION: Study Guide and Review - Chapter 1 State whether each sentence is true or false . If false , replace the underlined term to make a true sentence. 1. A function assigns every element of its domain to exactly one element of its range. A function f (x) with values that decrease as x increases is a decreasing function. 7. The extrema of a function can include relative maxima or minima. SOLUTION: Although there are other examples, the extrema of a function can include relative maxima or minima. SOLUTION: A function assigns every element of its domain to exactly one element of its range. When more than one element of the range is assigned to one element of the domain, then the relation is not a function. 2. Graphs that have point symmetry can be rotated 180° with respect to a point and appear unchanged. SOLUTION: 8. The translation of a graph produces a mirror image of the graph with respect to a line. SOLUTION: The reflection of a graph produces a mirror image of the graph with respect to a line. A translation produces a duplicate image of the graph, just moved vertically or horizontally. 9. A one-to-one function passes the horizontal line test. Graphs that have point symmetry can be rotated 180° with respect to a point and appear unchanged. 3 An example of this is the graph of f (x) = x which is symmetric with respect to the origin. 3. An odd function has a point of symmetry. SOLUTION: 3 An example of this is the graph of f (x) = x which is symmetric with respect to the origin. A function is odd when f (−x) = −f (x). SOLUTION: A function is one-to-one when every value of x is associated with a unique value of y. In the graph of this function, each individual y-value will occur only once. Because of this, no horizontal line will cross the graph at more than one point. 10. One-to-one functions have line symmetry. SOLUTION: Inverse functions have line symmetry because the −1 4. The graph of a continuous function has no breaks or holes. SOLUTION: The graph of a continuous function has no breaks or holes. If a function has a break or a hole, then it will not be continuous. 5. The limit of a graph is the concept of approaching a value without necessarily ever reaching it. SOLUTION: The end behavior of a graph is the concept of approaching a value without necessarily ever reaching it. The concept of a function approaching a value without necessarily reaching it is called a limit. 6. A function f (x) with values that decrease as x increases is a decreasing function. SOLUTION: graph of the inverse function f (x) and the graph of f(x) are symmetric with respect to the line y = x. Determine whether each relation represents y as a function of x. 11. 3x − 2y = 18 SOLUTION: This equation represents y as a function of x, because for every x-value there is exactly one corresponding y-value. The only linear equations that are not functions are of the form x = c. 12. y 3 − x = 4 SOLUTION: This equation represents y as a function of x, because for every x-value there is exactly one corresponding y-value. A sketch of the graph shows that the function passes the Vertical Line Test. A function f (x) with values that decrease as x increases is a decreasing function. 7. TheManual extrema of a function can eSolutions - Powered by Cognero maxima or minima. SOLUTION: include relative Page 1 SOLUTION: This equation represents y as a function of x, because for every x-value there is exactly one corresponding y-value. The only linear equations that Study Guide andare Review - Chapter 1 are not functions of the form x = c. 12. y 3 − x = 4 16. f (−3x) SOLUTION: SOLUTION: This equation represents y as a function of x, because for every x-value there is exactly one corresponding y-value. A sketch of the graph shows that the function passes the Vertical Line Test. State the domain of each function. 17. f (x) = 5x2 – 17x + 1 SOLUTION: There is no value of x that will make the function undefined, so D = {x| x R}. 18. g(x) = SOLUTION: The function is undefined when 6x − 3 < 0. 13. SOLUTION: This equation represents y as a function of x, because for every x-value there is exactly one corresponding y-value. D = {x | x ≥ 0.5, x R} 19. h(a) = SOLUTION: The function is undefined when a + 5 = 0. D = {a | a ≠ −5, a R} 20. v(x) = 14. SOLUTION: SOLUTION: This graph does not represent a function because it fails the Vertical Line Test. The function is undefined when x − 4 = 0. 2 2 Let f (x) = x − 3x + 4. Find each function value. 15. f (5) D = {x | x ≠ ±2, x SOLUTION: R} Use the graph of g to find the domain and range of each function. 16. f (−3x) eSolutions Manual - Powered by Cognero Page 2 SOLUTION: 21. Study Guide and Review - Chapter 1 D = {x | x ≠ ±2, x R} Use the graph of g to find the domain and range of each function. 24. f (x) = x2 – 6x − 27 SOLUTION: 21. SOLUTION: The x-values range from −8 to 8 and the y-values range from 0 to 8. D = [−8, 8], R = [0, 8] 25. f (x) = x3 − 16x SOLUTION: 22. SOLUTION: The arrows indicate that the x-values extend to negative infinity and positive infinity. The y-values extend to negative infinity and reach a maximum of −3. D = {x | x R}, R = (− , −3) 26. f (x) = − 1 SOLUTION: Find the y-intercept(s) and zeros for each function. 23. f (x) = 4x − 9 SOLUTION: Determine whether each function is continuous at the given x-value(s). Justify using the continuity test. If discontinuous, identify the type of discontinuity as infinite, jump , or removable. 27. f (x) = x2 – 3x; x = 4 SOLUTION: 24. f (x) = x2 – 6x − 27 Find f (4). SOLUTION: eSolutions Manual - Powered by Cognero The function is defined at x = 4. Page 3 Find . Construct a table that shows values of f (x) for x-values approaching 4 from the left and . Because Study Guide and Review - Chapter 1 Determine whether each function is continuous at the given x-value(s). Justify using the continuity test. If discontinuous, identify the type of discontinuity as infinite, jump , or removable. , f (x) is continuous as x = 4. 28. f (x) = ; x = 10 SOLUTION: Find f (10). 27. f (x) = x2 – 3x; x = 4 SOLUTION: Find f (4). The function is defined at x = 10. Find . Construct a table that shows values The function is defined at x = 4. Find . Construct a table that shows values of f (x) for x-values approaching 4 from the left and from the right. x f (x) 3.9 3.51 3.99 3.9501 3.999 3.995 4 4 4.001 4.005 4.01 4.0501 4.1 4.51 . Because Because , f (x) is continuous as x = 10. , f (x) is continuous as x = 29. f (x) = 4. 28. f (x) = of f (x) for x-values approaching 10 from the left and from the right. x f (x) 9.9 3.975 9.99 3.9975 9.999 3.9997 10 4 10.001 4.0002 10.01 4.0025 10.1 4.025 . ; x = 10 ; x = 0 and x = 7 SOLUTION: Find f (0). SOLUTION: Find f (10). The function is defined at x = 10. Find . Construct a table that shows values of f (x) for x-values approaching 10 from the left and from the right. x f (x) eSolutions Manual - Powered by Cognero The function is defined at x = 0. Find . Construct a table that shows values of f (x) for x-values approaching 0 from the left and from the right. Page 4 x f (x) −0.1 −0.0145 The function is defined at x = 0. Find . Construct a table that shows values Study Guide and Review - Chapter 1 of f (x) for x-values approaching 0 from the left and from the right. x −0.1 −0.01 −0.001 0 0.001 0.01 0.1 . ; x = 2 and x = 4 SOLUTION: Find f (2). f (x) −0.0145 −0.0014 −0.0001 0 0.0001 0.0014 0.01408 Because The function is undefined at x = 2. Find . Construct a table that shows values , f (x) is continuous as x = 0. Find f (7). The function is defined at x = 7. Find . Construct a table that shows values of f (x) for x-values approaching 7 from the left and from the right. x f (x) 6.9 0.4964 6.99 0.49964 6.999 0.49996 7 0.5 7.001 0.50004 7.01 0.50036 7.1 0.50355 . Because , f (x) is continuous as x = 7. 30. f (x) = 30. f (x) = ; x = 2 and x = 4 SOLUTION: Find f (2). eSolutions Manual - Powered by Cognero of f (x) for x-values approaching 2 from the left and from the right. x f (x) 1.9 −4.872 1.99 −49.87 1.999 −499.9 2 undefined 2.001 500.12 2.01 50.125 2.1 5.122 Because f (2) is undefined and f (x) approaches –∞ as x approaches 2 from the left and ∞ as x approaches 2 from the right, f (x) is discontinuous at x = 2 and has an infinite discontinuity at x = 2. Find f (4). The function is defined at x = 4. Find . Construct a table that shows values of f (x) for x-values approaching 4 from the left and from the right. x f (x) 3.9 0.3479 3.99 0.33473 3.999 0.33347 4 0.33333 Page 5 4.001 0.33319 4.01 0.33195 4.1 0.32006 from the right. x f (x) 3.9 0.3479 Study Guide and Review 3.99 0.33473 3.999 0.33347 4 0.33333 4.001 0.33319 4.01 0.33195 4.1 0.32006 . Because - Chapter 1 , f (x) is continuous as x = 1. Use the graph of each function to describe its end behavior. . Because , f (x) is continuous as x = 32. 4. SOLUTION: 31. ;x=1 Analyze the graph from left to right. The left side of the graph indicates where x approaches negative infinity while the right side indicates where x approaches positive infinity. From the graph, it appears that as x → , f (x) → − ; as x → − , f (x) → . SOLUTION: Find f (1). The function is defined at x = 1. Find . Construct a table that shows values of f (x) for x-values approaching 1 from the left and from the right. x f (x) 0.9 1.7 0.99 1.97 0.999 1.997 1 2 1.001 2.002 1.01 2.02 1.1 2.2 . Because 33. SOLUTION: Analyze the graph from left to right. The left side of the graph indicates where x approaches negative infinity while the right side indicates where x approaches positive infinity. From the graph, it appears that as x → , f (x) → 0; as x → − , f (x) → 0. Use the graph of each function to estimate intervals to the nearest 0.5 unit on which the function is increasing, decreasing, or constant. Then estimate to the nearest 0.5 unit, and classify the extrema for the graph of each function. , f (x) is continuous as x = 1. Use the graph of each function to describe its end behavior. 34. SOLUTION: 32. eSolutions Manual - Powered by Cognero SOLUTION: Analyze the graph from left to right. The left side of Page 6 Analyze the graph from left to right. As the graph changes from increasing to decreasing, there is a maximum. As the graph changes from decreasing to the graph indicates where x approaches negative infinity while the right side indicates where x approaches positive infinity. From the graph, it appears that and as x → , f (x) → 0; as x → Study Guide Review - Chapter−1 , f (x) → 0. Use the graph of each function to estimate intervals to the nearest 0.5 unit on which the function is increasing, decreasing, or constant. Then estimate to the nearest 0.5 unit, and classify the extrema for the graph of each function. 34. absolute extremum. f is decreasing on (− , −3), increasing on (−3, −1.5), decreasing on (−1.5, 0.5), and increasing on (0.5, ); relative minimum at (−3, 3), relative maximum at (−1.5, 6) and relative minimum at (0.5, −7). Find the average rate of change of each function on the given interval. 36. f (x) = −x3 + 3 x + 1; [0, 2] SOLUTION: 37. f (x) = x2 + 2x + 5; [−5, 3] SOLUTION: Analyze the graph from left to right. As the graph changes from increasing to decreasing, there is a maximum. As the graph changes from decreasing to increasing, there is a minimum. When the extremum is the farthest point on the graph, then it is an absolute extremum. f is increasing on (− , −0.5), decreasing on (−0.5, 0.5), and increasing on (0.5, ); relative maximum at (−0.5, 3.5) and relative minimum at (0.5, 2.5). SOLUTION: Identify the parent function f (x) of g(x), and describe how the graphs of g(x) and f (x) are related. Then graph f (x) and g(x) on the same axes. 38. g(x) = + 2 SOLUTION: g(x) = f (x − 3) + 2, so g(x) is the graph of f (x) = 35. SOLUTION: Analyze the graph from left to right. As the graph changes from increasing to decreasing, there is a maximum. As the graph changes from decreasing to increasing, there is a minimum. When the extremum is the farthest point on the graph, then it is an absolute extremum. f is decreasing on (− , −3), increasing on (−3, −1.5), decreasing on (−1.5, 0.5), and increasing on (0.5, ); relative minimum at (−3, 3), relative maximum at (−1.5, 6) and relative minimum at (0.5, −7). Find the average rate of change of each function on the given interval. 3 36. f (x) = −x + 3 x + 1; [0, 2] SOLUTION: eSolutions Manual - Powered by Cognero translated 3 units to the right and 2 units up. The translation right is represented by the subtraction of 3 inside the function. The translation up is represented by the addition of 2 on the outside of f (x). 39. g(x) = −(x – 6)2 − 5 SOLUTION: 2 g(x) = −f (x − 6) − 5, so g(x) is the graph of f (x) = x reflected in the x-axis and translated 6 units to the right and 5 units down. The translation right is Page 7 represented by the subtraction of 6 inside the function. The reflection is represented by the Study Guide and Review - Chapter 1 39. g(x) = −(x – 6)2 − 5 41. g(x) = [[x]] + 3 SOLUTION: g(x) = −f (x − 6) − 5, so g(x) is the graph of f (x) = x reflected in the x-axis and translated 6 units to the right and 5 units down. The translation right is represented by the subtraction of 6 inside the function. The reflection is represented by the negative coefficient of f (x). The translation down is represented by the subtraction of 5 outside of f (x). SOLUTION: 2 g(x) = compressed vertically by a factor of and translated 3 units up. The compression is represented by the coefficient of f (x). The translation is represented by the addition of 3 outside the function. 40. g(x) = Describe how the graphs of f (x) = and g(x) are related. Then write an equation for g(x). SOLUTION: g(x) = f (x) + 3, so g(x) is the graph of f (x) = [[x]] f (x + 7), so g(x) is the graph of f (x) = translated 7 units to the left and is compressed vertically by a factor of . The translation is 42. represented by the addition of 7 inside the function. The compression is represented by the coefficient of f(x). SOLUTION: The graph is translated 2 units left. This is done by adding 2 inside the function. g(x) = f (x + 2) = . 41. g(x) = 43. [[x]] + 3 SOLUTION: SOLUTION: g(x) = f (x) + 3, so g(x) is the graph of f (x) = [[x]] The graph is reflected in the x-axis and translated 4 units right and 1 unit up. This is done by multiplying f (x) by −1, subtracting 4 inside f (x) and adding 1 outside f (x). g(x) = −f (x − 4) + 1 = − compressed vertically by a factor eSolutions Manual - Powered by Cognero of and translated 3 units up. The compression is represented by the coefficient of f (x). The translation is + 1. Page 8 Find (f + g)(x), (f – g)(x), (f ⋅ g)(x), and (x) SOLUTION: , for which The graph is translated 2 units left. This is done by adding 2 inside the function. g(x) = f (x + 2) = . Even though there appears to be no restriction of −3 in the simplified function, there is in the original. Study Guide and Review - Chapter 1 . 45. SOLUTION: 43. SOLUTION: The graph is reflected in the x-axis and translated 4 units right and 1 unit up. This is done by multiplying f (x) by −1, subtracting 4 inside f (x) and adding 1 outside f (x). g(x) = −f (x − 4) + 1 = − Find (f + g)(x), (f – g)(x), (f ⋅ g)(x), and + 1. (x) D = (− for each f (x) and g(x). State the domain of each new function. , ) for all of the functions except , for which . 44. 46. SOLUTION: SOLUTION: D = (− , ) for all of the functions except , for which D = (− , ) for all of the functions except , for which . . Even though there appears to be no restriction of −3 in the simplified function, there is in the original. 47. 45. SOLUTION: eSolutions Manual - Powered by Cognero SOLUTION: Page 9 , for which . 1 Study Guide and Review - Chapter for every function. For each pair of functions, find [f (x), and [f g](2). 47. g](x), [g f ] 48. f (x) = 4x – 11; g(x) = 2x2 − 8 SOLUTION: SOLUTION: 49. f (x) = x2 + 2x + 8; g(x) = x −5 SOLUTION: for every function. For each pair of functions, find [f (x), and [f g](2). g](x), [g f ] 50. f (x) = x2 – 3x + 4; g(x) = x2 SOLUTION: 48. f (x) = 4x – 11; g(x) = 2x2 − 8 SOLUTION: Find f o g. 51. eSolutions Manual - Powered by Cognero SOLUTION: Page 10 The domain of f (x) is x ≠ 3. In order for the range of g(x) to correspond with this domain, g(x) ≠ 3. There are no more restrictions. Study Guide and Review - Chapter 1 [f g](x) = for x ≥ Graph each function using a graphing calculator, and apply the horizontal line test to determine whether its inverse function exists. Write yes or no. 53. f (x) = |x| + 6 Find f o g . 51. SOLUTION: The domain of f (x) is x ≠ 3. In order for the range of g(x) to correspond with this domain, g(x) ≠ 3. SOLUTION: This graph fails the Horizontal Line Test. 54. f (x) = x3 SOLUTION: There are no more restrictions. [f g](x) = 52. This graph passes the Horizontal Line Test. SOLUTION: The domain of f (x) = x > 2. In order for the range of g(x) to correspond with this domain, g(x) must be greater than or equal to 2. There are no more restrictions. [f g](x) = for x ≥ 55. f (x) = − SOLUTION: This graph passes the Horizontal Line Test. 56. f (x) = x3 – 4x2 SOLUTION: Graph each function using a graphing calculator, and apply the horizontal line test to determine whether its inverse function exists. Write yes or no. 53. f (x) = |x| + 6 SOLUTION: eSolutions Manual - Powered by Cognero This graph fails the Horizontal Line Test. Find the inverse function and state any Page 11 From the graph, the domain and range of f Study Guide and Review - Chapter 1 This graph passes the Horizontal Line Test. 56. f (x) = x3 – 4x2 correspond with the range and domain of f the domain of f is restricted to{x| x ≥ 4}. −1 when 58. y = −4x + 8 SOLUTION: SOLUTION: Interchange the variables and solve for y. This graph fails the Horizontal Line Test. Graph the functions. Find the inverse function and state any restrictions on the domain. 57. y = (x – 4)2 SOLUTION: Interchange the variables and solve for y. From the graph, the domain and range of f −1 correspond with the range and domain of f for all real numbers. Graph the functions. 59. y = 2 SOLUTION: Interchange the variables and solve for y. From the graph, the domain and range of f correspond with the range and domain of f the domain of f is restricted to{x| x ≥ 4}. 58. y = −4x + 8 SOLUTION: −1 when Graph the functions. Interchange the variables and solve for y. From the graph, the domain and range of f Graph the functions. correspond with the range and domain of f the domain of f is restricted to{x| x ≥ −3}. 60. y = eSolutions Manual - Powered by Cognero −1 when − 3 SOLUTION: Interchange the variables and solve for y. Page 12 From the graph, the domain and range of f −1 correspond range and-domain of f 1when Study Guidewith andtheReview Chapter the domain of f is restricted to{x| x ≥ −3}. 60. y = − 3 SOLUTION: Interchange the variables and solve for y. Graph the functions. From the graph, the domain and range of f −1 correspond with the range and domain of f when the domain of f is restricted to{x| x ≥ 0}. 61. CELL PHONES Basic Mobile offers a cell phone plan that charges $39.99 per month. Included in the plan are 500 daytime minutes that can be used Monday through Friday between 7 A.M. and 7 P.M. Users are charged $0.20 per minute for every daytime minute over 500 used. a. Write a function p (x) for the cost of a month of service during which you use x daytime minutes. b. How much will you be charged if you use 450 daytime minutes? 550 daytime minutes? c. Graph p (x). SOLUTION: From the graph, the domain and range of f −1 correspond with the range and domain of f when the domain of f is restricted to{x| x ≥ 0}. 61. CELL PHONES Basic Mobile offers a cell phone plan that charges $39.99 per month. Included in the plan are 500 daytime minutes that can be used Monday through Friday between 7 A.M. and 7 P.M. Users are charged $0.20 per minute for every daytime minute over 500 used. a. Write a function p (x) for the cost of a month of service during which you use x daytime minutes. b. How much will you be charged if you use 450 daytime minutes? 550 daytime minutes? c. Graph p (x). a. There is a base charge of $39.99 which you will pay regardless of the number of minutes you use. You also receive 500 free minutes, so if you use 500 or less minutes, then you will only be charged the base fee. Once you go over 500 minutes, then you will be charged the base fee plus $0.20x where x is the number of minutes over 500. This can be written using a piecewise function. b. For 450 minutes, you will only be charged the base fee. For 550 minutes, you will be charge the base fee plus $0.20(50). $39.99; $49.99 c. SOLUTION: a. There is a base charge of $39.99 which you will pay regardless of the number of minutes you use. You also receive 500 free minutes, so if you use 500 or less minutes, then you will only be charged the base fee. Once you go over 500 minutes, then you will be charged the base fee plus $0.20x where x is the number of minutes over 500. This can be written using a piecewise function. b. For 450 minutes, you will only be charged the base fee. For 550 minutes, you will be charge the base fee plus $0.20(50). $39.99; $49.99 c. eSolutions Manual - Powered by Cognero 62. AUTOMOBILES The fuel economy for a hybrid car at various highway speeds is shown. a. Approximately what is the fuel economy for the car when traveling 50 miles per hour? b. At approximately what speed will the car’s fuel economy be less than 40 miles per gallon? SOLUTION: Page 13 a. Analyze the graph. The speed is shown along the Study Guide and Review - Chapter 1 62. AUTOMOBILES The fuel economy for a hybrid car at various highway speeds is shown. Before her promotion, the graph of her salary is constant and will be represented by a horizontal line. After the promotion, the graph will jump up and then be represented by a new horizontal line. There will be a jump discontinuity at this point. 64. BASEBALL The table shows the number of home runs by a baseball player in each of the first 5 years he played professionally. a. Approximately what is the fuel economy for the car when traveling 50 miles per hour? b. At approximately what speed will the car’s fuel economy be less than 40 miles per gallon? a. Explain why 2006 represents a relative minimum. b. Suppose the average rate of change of home runs between 2008 and 2011 is 5 home runs per year. How many home runs were there in 2011? c. Suppose the average rate of change of home runs between 2007 and 2012 is negative. Compare the number of home runs in 2007 and 2012. SOLUTION: SOLUTION: a. Analyze the graph. The speed is shown along the x-axis. Scroll to where the speed is 50 mph and then look up to where the graph is at that point. It appears to be near 51 mi/g. Sample answer: approximately 51 mpg b. Analyze the graph. The fuel economy is shown along the y-axis. Scroll to where the fuel economy is 40 mi/g and then look to where the graph is at that point. It appears to be near 67 mph. Sample answer: approximately 67 mph or faster a. Sample answer: The number of home runs decreased, then increased. This tells us that there is a minimum. Also, the value of 23 is not the smallest value on the graph. Therefore, the minimum is local and not absolute. b. 42 · 3(5) = 57 c. When the average rate of change is negative from point a to point b, then the graph has decreased from a to b. There were fewer home runs in 2012 than in 2007. 63. SALARIES After working for a company for five 65. PHYSICS A stone is thrown horizontally from the years, Ms. Washer was given a promotion. She is now earning $1500 per month more than her previous salary. Will a function modeling her monthly income be a continuous function? Explain. top of a cliff. The velocity of the stone measured in meters per second after t seconds can be modeled by v(t) = –9.8t + 7. The speed of the stone is the absolute value of its velocity. Draw a graph of the stone’s speed during the first 6 seconds. SOLUTION: SOLUTION: Before her promotion, the graph of her salary is constant and will be represented by a horizontal line. After the promotion, the graph will jump up and then be represented by a new horizontal line. There will be a jump discontinuity at this point. Graph y = 64. BASEBALL The table shows the number of home runs by a baseball player in each of the first 5 years he played professionally. a. Explain why 2006 represents a relative minimum. b. Suppose the average rate of change of home runs between 2008 and 2011 is 5 home runs per year. How many home runs were there in 2011? c. Suppose the average rate of change of home runs between 2007 and 2012 is negative. Compare the eSolutions Manual - Powered by Cognero number of home runs in 2007 and 2012. SOLUTION: 66. FINANCIAL LITERACY A department store advertises $10 off the price of any pair of jeans. How much will a pair of jeans cost if the original Page 14 price is $55 and there is 8.5% sales tax? SOLUTION: Study Guide and Review - Chapter 1 66. FINANCIAL LITERACY A department store advertises $10 off the price of any pair of jeans. How much will a pair of jeans cost if the original price is $55 and there is 8.5% sales tax? SOLUTION: Multiply the tax percentage by the price. This is your total tax. Add this to the price and you get the total price. 55 · 1.085 ≈ 48.83 67. MEASUREMENT One inch is approximately equal to 2.54 centimeters. a. Write a function A(x) that will convert the area x of a rectangle from square inches to square centimeters. −1 b. Write a function A (x) that will convert the area x of a rectangle from square centimeters to square inches. SOLUTION: a. If one inch equals 2.54 centimeters, then 1 square 2 inch will equal 2.54 centimeters. b. The inverse of multiplying by a number is dividing by that same number. −1 A (x) = x eSolutions Manual - Powered by Cognero Page 15