Section Exercises

1. Explain why we cannot find inverse functions for all polynomial functions.

2. Why must we restrict the domain of a quadratic function when finding its inverse?

3. When finding the inverse of a radical function, what restriction will we need to make?

4. The inverse of a quadratic function will always take what form?

For the following exercises, find the inverse of the function on the given domain.

5. f(x)=(x4)2,[4,)

6. f(x)=(x+2)2,[2,)

7. f(x)=(x+1)23,[1,)

8. f(x)=23+x

9. f(x)=3x2+5,(,0],[0,)

10. f(x)=12x2,[0,)

11. f(x)=9x2,[0,)

12. f(x)=2x2+4,[0,)

For the following exercises, find the inverse of the functions.

13. f(x)=x3+5

14. f(x)=3x3+1

15. f(x)=4x3

16. f(x)=42x3

For the following exercises, find the inverse of the functions.

17. f(x)=2x+1

18. f(x)=34x

19. f(x)=9+4x4

20. f(x)=6x8+5

21. f(x)=9+2x3

22. f(x)=3x3

23. f(x)=2x+8

24. f(x)=3x4

25. f(x)=x+3x+7

26. f(x)=x2x+7

27. f(x)=3x+454x

28. f(x)=5x+125x

29. f(x)=x2+2x,[1,)

30. f(x)=x2+4x+1,[2,)

31. f(x)=x26x+3,[3,)

For the following exercises, find the inverse of the function and graph both the function and its inverse.

32. f(x)=x2+2,x0

33. f(x)=4x2,x0

34. f(x)=(x+3)2,x3

35. f(x)=(x4)2,x4

36. f(x)=x3+3

37. f(x)=1x3

38. f(x)=x2+4x,x2

39. f(x)=x26x+1,x3

40. f(x)=2x

41. f(x)=1x2,x0

For the following exercises, use a graph to help determine the domain of the functions.

42. f(x)=(x+1)(x1)x

43. f(x)=(x+2)(x3)x1

44. f(x)=x(x+3)x4

45. f(x)=x2x20x2

46. f(x)=9x2x+4

For the following exercises, use a calculator to graph the function. Then, using the graph, give three points on the graph of the inverse with y-coordinates given.

47. f(x)=x3x2,y=1,2,3

48. f(x)=x3+x2,y=0,1,2

49. f(x)=x3+3x4,y=0,1,2

50. f(x)=x3+8x4,y=1,0,1

51. f(x)=x4+5x+1,y=1,0,1

For the following exercises, find the inverse of the functions with a, b, c positive real numbers.

52. f(x)=ax3+b

53. f(x)=x2+bx

54. f(x)=ax2+b

55. f(x)=ax+b3

56. f(x)=ax+bx+c

For the following exercises, determine the function described and then use it to answer the question.

57. An object dropped from a height of 200 meters has a height, h(t), in meters after t seconds have lapsed, such that h(t)=2004.9t2. Express t as a function of height, h, and find the time to reach a height of 50 meters.

58. An object dropped from a height of 600 feet has a height, h(t), in feet after t seconds have elapsed, such that h(t)=60016t2. Express as a function of height h, and find the time to reach a height of 400 feet.

59. The volume, V, of a sphere in terms of its radius, r, is given by V(r)=43πr3. Express r as a function of V, and find the radius of a sphere with volume of 200 cubic feet.

60. The surface area, A, of a sphere in terms of its radius, r, is given by A(r)=4πr2. Express r as a function of V, and find the radius of a sphere with a surface area of 1000 square inches.

61. A container holds 100 ml of a solution that is 25 ml acid. If n ml of a solution that is 60% acid is added, the function C(n)=25+.6n100+n gives the concentration, C, as a function of the number of ml added, n. Express n as a function of C and determine the number of mL that need to be added to have a solution that is 50% acid.

62. The period T, in seconds, of a simple pendulum as a function of its length l, in feet, is given by T(l)=2πl32.2. Express l as a function of T and determine the length of a pendulum with period of 2 seconds.

63. The volume of a cylinder, V, in terms of radius, r, and height, h, is given by V=πr2h. If a cylinder has a height of 6 meters, express the radius as a function of V and find the radius of a cylinder with volume of 300 cubic meters.

64. The surface area, A, of a cylinder in terms of its radius, r, and height, h, is given by A=2πr2+2πrh. If the height of the cylinder is 4 feet, express the radius as a function of V and find the radius if the surface area is 200 square feet.

65. The volume of a right circular cone, V, in terms of its radius, r, and its height, h, is given by V=13πr2h. Express r in terms of h if the height of the cone is 12 feet and find the radius of a cone with volume of 50 cubic inches.

66. Consider a cone with height of 30 feet. Express the radius, r, in terms of the volume, V, and find the radius of a cone with volume of 1000 cubic feet.