Problem Set 2: Domain and Range

1. Why does the domain differ for different functions?

2. How do we determine the domain of a function defined by an equation?

3. Explain why the domain of f(x)=3x is different from the domain of f(x)=x.

4. When describing sets of numbers using interval notation, when do you use a parenthesis and when do you use a bracket?

5. How do you graph a piecewise function?

For the following exercises, find the domain of each function using interval notation.

6. f(x)=2x(x1)(x2)

7. f(x)=52x2

8. f(x)=3x2

9. f(x)=362x

10. f(x)=43x

11. f(x)=x2+4

12. f(x)=312x

13. f(x)=3x1

14. f(x)=9x6

15. f(x)=3x+14x+2

16. f(x)=x+4x4

17. f(x)=x3x2+9x22

18. f(x)=1x2x6

19. f(x)=2x3250x22x15

20. 5x3

21. 2x+15x

22. f(x)=x4x6

23. f(x)=x6x4

24. f(x)=xx

25. f(x)=x29xx281

26. Find the domain of the function f(x)=2x350x by:

a. using algebra.
b. graphing the function in the radicand and determining intervals on the x-axis for which the radicand is nonnegative.

For the following exercises, write the domain and range of each function using interval notation.

27.

Graph of a function from (2, 8].

Domain: ________ Range: ________

28.

 

 

Graph of a function from [4, 8).

29.

Graph of a function from [-4, 4].

30.

 

Graph of a function from [2, 6].

31.

Graph of a function from [-5, 3).

32.

Graph of a function from [-3, 2).

33.

Graph of a function from (-infinity, 2].

34.

Graph of a function from [-4, infinity).

35.

Graph of a function from [-6, -1/6]U[1/6, 6]/.

36.

Graph of a function from (-2.5, infinity).

37.

Graph of a function from [-3, infinity).

For the following exercises, sketch a graph of the piecewise function. Write the domain in interval notation.

38. f(x)={x+1 if x<22x3 if x2 39. f(x)={2x1 if x<11+x if x1 40. f(x)={x+1 if x<0x1 if x>0

41. f(x)={3 if x<0x if x0 42. f(x)={x2 if x<01x if x>0

43. f(x)={x2 if x<0x+2 if x0 44. f(x)={x+1ifx<1x3ifx1 45. f(x)={|x| if x<21 if x2 For the following exercises, given each function f, evaluate f(3),f(2),f(1), and f(0). 46. f(x)={x+1 if x<22x3 if x2 47. f(x)={1 if x30 if x>3

48. f(x)={2x2+3 if x15x7 if x>1
For the following exercises, given each function f, evaluate f(1),f(0),f(2), and f(4).

49. f(x)={7x+3 if x<07x+6 if x0 50. f(x)={x22 if x<24+|x5| if x2 51. f(x)={5xifx<03if0x3x2ifx>3
For the following exercises, write the domain for the piecewise function in interval notation.

52. f(x)={x+1 if x<22x3 if x2 53. f(x)={x22 ifx<1x2+2 if x>1

54. f(x)={2x3 if x<03x2 if x2 55. Graph y=1x2 on the viewing window [0.5,0.1] and [0.1,0.5]. Determine the corresponding range for the viewing window. Show the graphs. 56. Graph y=1x on the viewing window [0.5,0.1] and [0.1, 0.5]. Determine the corresponding range for the viewing window. Show the graphs. 57. Suppose the range of a function f is [5, 8]. What is the range of |f(x)|? 58. Create a function in which the range is all nonnegative real numbers. 59 .Create a function in which the domain is x>2.

60. The cost in dollars of making x items is given by the function C(x)=10x+500.

A. The fixed cost is determined when zero items are produced. Find the fixed cost for this item.
B. What is the cost of making 25 items?
C. Suppose the maximum cost allowed is $1500. What are the domain and range of the cost function, C(x)?

61. The height h of a projectile is a function of the time t it is in the air. The height in feet for t seconds is given by the function h(t)=16t2+96t. What is the domain of the function? What does the domain mean in the context of the problem?