274 CHAPTER 2 Graphs and Functions x y 9 4 –2 –4 0 3 x = y2 −10 −10 10 10 y1 = !x y2 = −!x (b) Figure 69 (a) Selected Ordered Pairs for x =y2 x y 0 0 1 {1 4 {2 9 {3 There are two different y-values for the same x-value. 2.6 Exercises A. 2 –8 8 0 x y B. 1 2 3 1 2 3 0 x y C. 4 2 –2 0 x y D. E. F. 1 4 0 x 2 1 y 1 2 0 x 4 y x y 1 1 G. 1 2 2 0 x y H. 2 8 –8 –2 2 8 x y I. –2 2 2 0 x y 1. Which one is the graph of ƒ1x2 = x2? What is its domain? 2. Which one is the graph of ƒ1x2 = 0 x 0 ? On what open interval is it increasing? 3. Which one is the graph of ƒ1x2 = x3? What is its range? 4. Which one is not the graph of a function? What is its equation? 5. Which one is the identity function? What is its equation? 6. Which one is the graph of ƒ1x2 = Œxœ? What is the function value when x = 1.5? 7. Which one is the graph of ƒ1x2 = 23 x? Is there any open interval over which the function is decreasing? 8. Which one is the graph of ƒ1x2 = 2x? What is its domain? 9. Which one is discontinuous at many points? What is its range? 10. Which graphs of functions decrease over part of the domain and increase over the rest of the domain? On what open intervals do they increase? decrease? CONCEPT PREVIEW To answer each question, refer to the following basic graphs.
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