Section Exercises

1. The inverse of every logarithmic function is an exponential function and vice-versa. What does this tell us about the relationship between the coordinates of the points on the graphs of each?

2. What type(s) of translation(s), if any, affect the range of a logarithmic function?

3. What type(s) of translation(s), if any, affect the domain of a logarithmic function?

4. Consider the general logarithmic function f(x)=logb(x). Why can’t x be zero?

5. Does the graph of a general logarithmic function have a horizontal asymptote? Explain.

For the following exercises, state the domain and range of the function.

6. f(x)=log3(x+4)

7. h(x)=ln(12x)

8. g(x)=log5(2x+9)2

9. h(x)=ln(4x+17)5

10. f(x)=log2(123x)3

For the following exercises, state the domain and the vertical asymptote of the function.

11. f(x)=logb(x5)

12. g(x)=ln(3x)

13. f(x)=log(3x+1)

14. f(x)=3log(x)+2

15. g(x)=ln(3x+9)7

For the following exercises, state the domain, vertical asymptote, and end behavior of the function.

16. f(x)=ln(2x)

17. f(x)=log(x37)

18. h(x)=log(3x4)+3

19. g(x)=ln(2x+6)5

20. f(x)=log3(155x)+6

For the following exercises, state the domain, range, and x- and y-intercepts, if they exist. If they do not exist, write DNE.

21. h(x)=log4(x1)+1

22. f(x)=log(5x+10)+3

23. g(x)=ln(x)2

24. f(x)=log2(x+2)5

25. h(x)=3ln(x)9

For the following exercises, match each function in the graph below with the letter corresponding to its graph.
Graph of five logarithmic functions.

26. d(x)=log(x)

27. f(x)=ln(x)

28. g(x)=log2(x)

29. h(x)=log5(x)

30. j(x)=log25(x)

For the following exercises, match each function in the figure below with the letter corresponding to its graph.
Graph of three logarithmic functions.

31. f(x)=log13(x)

32. g(x)=log2(x)

33. h(x)=log34(x)

For the following exercises, sketch the graphs of each pair of functions on the same axis.

34. f(x)=log(x) and g(x)=10x

35. f(x)=log(x) and g(x)=log12(x)

36. f(x)=log4(x) and g(x)=ln(x)

37. f(x)=ex and g(x)=ln(x)

For the following exercises, match each function in the graph below with the letter corresponding to its graph.
Graph of three logarithmic functions.
38. f(x)=log4(x+2)

39. g(x)=log4(x+2)

40. h(x)=log4(x+2)

For the following exercises, sketch the graph of the indicated function.

41. f(x)=log2(x+2)

42. f(x)=2log(x)

43. f(x)=ln(x)

44. g(x)=log(4x+16)+4

45. g(x)=log(63x)+1

46. h(x)=12ln(x+1)3

For the following exercises, write a logarithmic equation corresponding to the graph shown.

47. Use y=log2(x) as the parent function.
The graph y=log_2(x) has been reflected over the y-axis and shifted to the right by 1.

48. Use f(x)=log3(x) as the parent function.
The graph y=log_3(x) has been reflected over the x-axis, vertically stretched by 3, and shifted to the left by 4.

49. Use f(x)=log4(x) as the parent function.
The graph y=log_4(x) has been vertically stretched by 3, and shifted to the left by 2.

50. Use f(x)=log5(x) as the parent function.
The graph y=log_3(x) has been reflected over the x-axis and y-axis, vertically stretched by 2, and shifted to the right by 5.

For the following exercises, use a graphing calculator to find approximate solutions to each equation.

51. log(x1)+2=ln(x1)+2

52. log(2x3)+2=log(2x3)+5

53. ln(x2)=ln(x+1)

54. 2ln(5x+1)=12ln(5x)+1

55. 13log(1x)=log(x+1)+13

56. Let b be any positive real number such that b1. What must logb1 be equal to? Verify the result.

57. Explore and discuss the graphs of f(x)=log12(x) and g(x)=log2(x). Make a conjecture based on the result.

58. Prove the conjecture made in the previous exercise.

59. What is the domain of the function f(x)=ln(x+2x4)? Discuss the result.

60. Use properties of exponents to find the x-intercepts of the function f(x)=log(x2+4x+4) algebraically. Show the steps for solving, and then verify the result by graphing the function.