Practice Test - Chapter 1 Determine whether the given relation represents y as a function of x. 4. PARKING The cost of parking a car downtown is $0.75 per 30 minutes for a maximum of $4.50. Parking is charged per second. a. Write a function for c(x), the cost of parking a car for x hours. b. Find c(2.5). c. What is the domain for c(x)? Explain your reasoning. 1. y 3 – x = 5 SOLUTION: When x = 1, y = ± . Therefore, the relation is not one-to-one and not a function. SOLUTION: a. A cost of $0.75 per 30 minutes is equal to a cost of $1.50 per hour. The charge maximizes at $4.50 so will remain unchanged when the car is parked for longer than 3 hours. c(x) = 2. b. 2.5 · 1.5 = 3.75 c. D = [0, 3]; Sample answer: The number of hours must be greater than or equal to 0. SOLUTION: The graph passes the Vertical Line Test, so the relation is a function. State the domain and range of each function. 3. y = SOLUTION: For every x-value, there is only one corresponding yvalue. Therefore, the relation is one-to-one and a function. Also, the graph of the relation passes the Vertical Line Test. 5. SOLUTION: The graph continues for all values of x and has a minimum y-value of −3. D = (− , ), R = [−3, ) 4. PARKING The cost of parking a car downtown is $0.75 per 30 minutes for a maximum of $4.50. Parking is charged per second. a. Write a function for c(x), the cost of parking a car for x hours. b. Find c(2.5). c. What is the domain for c(x)? Explain your reasoning. SOLUTION: a. A cost of $0.75 per 30 minutes is equal to a cost of $1.50 per hour. The charge maximizes at $4.50 so will remain unchanged when the car is parked for longer than 3 hours. eSolutions Manual - Powered by Cognero c(x) = 6. SOLUTION: The graph continues for all values of x such that x ≤ 5 and has a minimum y-value of 0. D = (− , 5], R = [0, ) Find the y-intercept(s) and zeros for each function. 7. f (x) = 4x2 – 8x − 12 SOLUTION: Page 1 SOLUTION: (x, −y) (0.25, −1) (1, −2) (−2.25, 3) (−4, 4) (0.25, 1) (1, 2) (2.25, 3) (4, 4) The graph continues for all values of x such that x ≤ 5 and has a minimum y-value1of 0. D = (− , 5], R = Practice Test - Chapter [0, ) Find the y-intercept(s) and zeros for each function. 7. f (x) = 4x2 – 8x − 12 Determine whether each function is continuous at x = 3. If discontinuous, identify the type of discontinuity as infinite, jump , or removable. 10. SOLUTION: SOLUTION: f(3) = 6, , The function is continuous at x = 3. 11. f (x) = SOLUTION: 3 2 8. f (x) = x + 4x + 3x SOLUTION: not continuous; removable discontinuity at x = 3 Find the average rate of change for each function on the interval [−2, 6]. 12. f (x) = −x4 + 3x SOLUTION: 9. MULTIPLE CHOICE Which relation is symmetric about the x-axis? A −x2 − yx = 2 3 B x y = −8 C y = |x| D −y 2 = −4x SOLUTION: In order for a relation to be symmetric with respect to the x-axis, (x, y) must correspond with (x, −y). This occurs for choice D only. (x, y) (x, −y) (0.25, 1) (0.25, −1) (1, 2) (1, −2) (2.25, 3) (−2.25, 3) (4, 4) (−4, 4) 13. f (x) = SOLUTION: Determine whether each function is continuous at x = 3. If discontinuous, identify the type of discontinuity as infinite, jump , or removable. 10. eSolutions Manual - Powered by Cognero Page 2 SOLUTION: f(3) = 6, , Use the graph of each function to estimate SOLUTION: Practice Test - Chapter 1 f is decreasing on (− , −1.5), increasing on (−1.5, 0), decreasing on (0, 1.5), and increasing on (1.5, ). 16. Which function is shown in the graph? 13. f (x) = SOLUTION: F f (x) = |x − 4| − 3 G f (x) = |x − 4| + 3 H f (x) = |x + 4| − 3 J f (x) = |x + 4| + 3 SOLUTION: Use the graph of each function to estimate intervals to the nearest 0.5 unit on which the function is increasing or decreasing. The parent function g(x) = | x | is shifted down 3 units. Therefore, F and H are possible choices. The graph is also shifted 4 units left, which corresponds to choice H. Identify the parent function f (x) of g(x). Then sketch the graph of g(x). 17. g(x) = −(x + 3)3 SOLUTION: f(x) = x 14. 3 SOLUTION: f is increasing on (− ). , 2.5) and decreasing on (2.5, 18. g(x) = |x2 − 4| SOLUTION: 15. SOLUTION: f(x) = x 2 f is decreasing on (− , −1.5), increasing on (−1.5, 0), decreasing on (0, 1.5), and increasing on (1.5, ). 16. Which function is shown in the graph? eSolutions Manual - Powered by Cognero Page 3 Given f (x) = x − 6 and g(x) = x 2 − 36, find each function and its domain. Practice Test - Chapter 1 There are no restrictions on the domain. Given f (x) = x − 6 and g(x) = x 2 − 36, find each function and its domain. 19. 21. TEMPERATURE In most countries, temperature is measured in degrees Celsius. The equation that relates degrees Fahrenheit with degrees Celsius is F = SOLUTION: C + 32. a. Write C as a function of F. b. Find two functions f and g such that C = [f (F). g] SOLUTION: a. The value of x cannot equal −6 or 6. In the original expression, if x = 6 or −6, a division by 0 would occur, which is undefined. 20. [g f ](x) b. When making a composition, look for the operation that must be done first. This will represent the innermost function in the composition, in this case, g(x). Sample answer: (x) = SOLUTION: x; g(x) = x − 32 Determine whether f has an inverse function. If it does, find the inverse function and state any restrictions on its domain. 22. f (x) = (x – 2)3 SOLUTION: Graph f (x). There are no restrictions on the domain. 21. TEMPERATURE In most countries, temperature is measured in degrees Celsius. The equation that relates degrees Fahrenheit with degrees Celsius is F = C + 32. a. Write C as a function of F. b. Find two functions f and g such that C = [f (F). g] The graph passes the Horizontal Line Test. Therefore, an inverse exists. SOLUTION: a. There is no domain restriction. b. When making a composition, look for the This will represent the innermost function in the composition, in this eSolutions Manual that - Powered operation mustbybeCognero done first. case, g(x). Sample answer: (x) = x; g(x) = x − 32 23. f (x) = SOLUTION: Page 4 Practice - Chapter 1 There isTest no domain restriction. The domain of f −1 (x) is x ≠ 1. 24. f (x) = 23. f (x) = SOLUTION: SOLUTION: Graph f (x). Graph f (x). The graph passes the Horizontal Line Test. Therefore, an inverse exists. The graph passes the Horizontal Line Test. Therefore, an inverse exists. Graph the inverse. Graph the inverse. The range of f (x) = [0, ∞), so the domain of f must be limited to [0, ∞). −1 (x) 25. f (x) = x2 – 16 The domain of f −1 (x) is x ≠ 1. 24. f (x) = SOLUTION: Graph f (x). SOLUTION: Graph f (x). eSolutions Manual - Powered by Cognero The graph does not pass the Horizontal Line Test. Page 5 Therefore, an inverse does not exist. The range of f -(x) = [0, ∞), so the domain of f Practice Test Chapter 1 −1 (x) must be limited to [0, ∞). 25. f (x) = x2 – 16 SOLUTION: Graph f (x). The graph does not pass the Horizontal Line Test. Therefore, an inverse does not exist. eSolutions Manual - Powered by Cognero Page 6
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