Problem Set 48: Graphs of the Sine and Cosine Function

1. Why are the sine and cosine functions called periodic functions?

2. How does the graph of y=sinx compare with the graph of y=cosx? Explain how you could horizontally translate the graph of y=sinx to obtain y=cosx.

3. For the equation Acos(Bx+C)+D, what constants affect the range of the function and how do they affect the range?

4. How does the range of a translated sine function relate to the equation y=Asin(Bx+C)+D?

5. How can the unit circle be used to construct the graph of f(t)=sint?

6. f(x)=2sinx

7. f(x)=23cosx

8. f(x)=3sinx

9. f(x)=4sinx

10. f(x)=2cosx

11. f(x)=cos(2x)

12. f(x)=2sin(12x)

13. f(x)=4cos(πx)

14. f(x)=3cos(65x)

15. y=3sin(8(x+4))+5

16. y=2sin(3x21)+4

17. y=5sin(5x+20)2

For the following exercises, graph one full period of each function, starting at x=0. For each function, state the amplitude, period, and midline. State the maximum and minimum y-values and their corresponding x-values on one period for x>0. State the phase shift and vertical translation, if applicable. Round answers to two decimal places if necessary.

18. f(t)=2sin(t5π6)

19. f(t)=cos(t+π3)+1

20. f(t)=4cos(2(t+π4))3

21. f(t)=sin(12t+5π3)

22. f(x)=4sin(π2(x3))+7

23. Determine the amplitude, midline, period, and an equation involving the sine function for the graph shown in Figure 26.

A sinusoidal graph with amplitude of 2, range of [-5, -1], period of 4, and midline at y=-3.

Figure 26

24. Determine the amplitude, period, midline, and an equation involving cosine for the graph shown in Figure 27.

A graph with a cosine parent function, with amplitude of 3, period of pi, midline at y=-1, and range of [-4,2]

Figure 27

25. Determine the amplitude, period, midline, and an equation involving cosine for the graph shown in Figure 28.

A graph with a cosine parent function with an amplitude of 2, period of 5, midline at y=3, and a range of [1,5].

Figure 28

26. Determine the amplitude, period, midline, and an equation involving sine for the graph shown in Figure 29.

A sinusoidal graph with amplitude of 4, period of 10, midline at y=0, and range [-4,4].

Figure 29

27. Determine the amplitude, period, midline, and an equation involving cosine for the graph shown in Figure 30.

A graph with cosine parent function, range of function is [-4,4], amplitude of 4, period of 2.

Figure 30

28. Determine the amplitude, period, midline, and an equation involving sine for the graph shown in Figure 31.

A graph with sine parent function. Amplitude 2, period 2, midline y=0

Figure 31

29. Determine the amplitude, period, midline, and an equation involving cosine for the graph shown in Figure 32.

A graph with cosine parent function. Amplitude 2, period 2, midline y=1

Figure 32

30. Determine the amplitude, period, midline, and an equation involving sine for the graph shown in Figure 33.

A graph with a sine parent function. Amplitude 1, period 4 and midline y=0.

Figure 33

For the following exercises, let f(x)=sinx.

31. On [0,2π), solve f(x)=12.

32. Evaluate f(π2).

33. On [0,2π), f(x)=22. Find all values of x.

34. On [0,2π), the maximum value(s) of the function occur(s) at what x-value(s)?

35. On [0,2π), the minimum value(s) of the function occur(s) at what x-value(s)?

36. Show that f(x)=f(x).This means that f(x)=sinx is an odd function and possesses symmetry with respect to ________________.

For the following exercises, let f(x)=cosx.

37. On [0,2π), solve the equation f(x)=cosx=0.

38. On[0,2π), solve f(x)=12.

39. On [0,2π), find the x-intercepts of f(x)=cosx.

40. On [0,2π), find the x-values at which the function has a maximum or minimum value.

41. On [0,2π), solve the equation f(x)=32.

42. Graph h(x)=x+sinx on[0,2π]. Explain why the graph appears as it does.

43. Graph h(x)=x+sinx on[−100,100]. Did the graph appear as predicted in the previous exercise?

44. Graph f(x)=xsinx on [0,2π] and verbalize how the graph varies from the graph of f(x)=sinx.

45. Graph f(x)=xsinx on the window [−10,10] and explain what the graph shows.

46. Graph f(x)=sinxx on the window [−5π,5π] and explain what the graph shows.

47. A Ferris wheel is 25 meters in diameter and boarded from a platform that is 1 meter above the ground. The six o’clock position on the Ferris wheel is level with the loading platform. The wheel completes 1 full revolution in 10 minutes. The function h(t) gives a person’s height in meters above the ground t minutes after the wheel begins to turn.
a. Find the amplitude, midline, and period of h(t).
b. Find a formula for the height function h(t).
c. How high off the ground is a person after 5 minutes?