Dr. J's Maths.com
Where the techniques of Maths
are explained in simple terms.

Trigonometric functions - Graphing and interpretation.
Test Yourself 1.


 

Given an equation, describe the features
(include references to shifts and dilations).
1. Describe the main features for the curve y = 3cos 2x.
2. Describe the main features for the curve y = 2 + sin x.
3. Describe the main features for the curve y = 2 - 3 cos 4x.
4. Describe the main features for the curve .
  5. Describe the main features for the curve

Given a graph, interpret the features
(include references to shifts and dilations).
6.

The graph above can be represented by an equation of the form
y = a cos nx
.

Find the values of a and n.

Answer.a = 2 and n = π/2.
  7. The equation of the following graph is written in the form
y = A + B cos(Cx - D).

Determine the values of A, B, C and D.

Answer.A = 4, B = 2, C = 1 and D = 0.
  8. The equation of the following graph is written in the form
y = A + B tan(Cx + D).

Determine the values of A, B, C and D.

Answer.A = 0, B = 3, C = 2 and D = 0.
  9. The equation of the following graph is written in the form
y = A + B sin(Cx + D).

Determine the values of A, B, C and D.

Answer.A = 3, B = 2, C = 1 and D = -π/3.
  10. The graph of D = A + Bcos Ct is given below.

(i) State the amplitude and period of the curve.

(ii) Hence or otherwise determine the values of A, B and C.

Answer.A = -3, B = 2, C = π.
  11. What is the equation for the curve shown in the diagram below?
Explain your reasons for your answer.

Sketch graphs with transformations. 12. Sketch y = cos t + 2 for t:[0, 2π].
  13. For the function y = 2 cos x

(i) State the amplitude of this function.

(ii) Determine the period of the function.

(iii) sketch the function for x:[0, 2π]..

  14. For the function y = -2 sin 3x;

(i) State the period.

(ii) Sketch the graph of the function for x:[0, π].

  15. Draw sketches, on the same axes, of the curves
and in the domain
of x:[0, 4].
  16. Sketch the curve y = 1 - 2 sin 2t for 0 ≤ t ≤ 2π.
  17. Sketch the curve y = -3 + 2 cos πt for 0 ≤ t ≤ 2π.
  18. Sketch the curve y = 2 + 3tan 2t for -π ≤ t ≤ π.
  19. Sketch the curve y = 2 - 3 sin (t - ) for 0 ≤ t ≤ 2π.
  20. (i) Sketch the graph of y = 1 - 2cos x for 0 ≤x ≤ 2π.
Clearly indicate the end points of the curve in its given domain as well as its turning points.

(ii) Use your graph to solve 1 - 2cos x = 0 in the given domain.

  21. (i) Sketch the curves y = sin x and y = cos x on the same axes for 0 ≤ x ≤ 2π.

(ii) By adding ordinates, develop the graph of y = sin x + cos x.

Graphs of reciprocal functions. 22. Sketch the curve y = 2 cosec 2x for 0° ≤ x ≤ 360°.
  23. Sketch the curve y = cot 2t for 0° ≤ t ≤ 360°.
  24. Sketch the curve y = sec x + 2 for 0 ≤x ≤ 2π.
  25. Sketch the curve y = sec2 x for 0 ≤x ≤ 2π.
  26. Sketch the curve y = 2 cot2 t for -π ≤ t ≤ π.
  27. Sketch the curve y = 2 - cosec x for -3π/2 ≤ x ≤ 3π/2.
Given features, draw the graph. 28. Draw a sine graph which has a maximum value of 7 and a minimum value of 1 and has two patterns in its domain of
0 ≤x ≤ 2π.
  29. Draw a tan graph using the domain 0 ≤x ≤ 2π with the function having consecutive values of 0 at x = 0 and at x = π/4 and also a value of 5 at x = π/8.
  30. Draw a sec graph which has minimum values of 2 at t = 0 and at t = 2π and a maximum value of -2 at t = π.
Use the domain of -2π ≤ t ≤ 2π.
  31. Draw a cosine graph having a minimum value of -4 at x = 0, a maximum value of 0 and having two patterns in its domain of
0 ≤x ≤ 2π.
Determining the number of solutions. 32. (i) Sketch the graph of y = 2cos 2x for x π.

(ii) On the same diagram, sketch the line x + y = 1.

(iii) Hence determine the number of solutions of the equation

2 cos2x = 1 - x.

(iv) Let the negative solution to 2 cos 2x = 1 - x be
at x = N.
Indicate N on the x-axis of your diagram.

  33. (i) Sketch the graphs of y = 3 cos 2θ and y = 1 for 0 ≤ θ ≤ π.

(ii) Use your graphs to obtain two approximate solutions to the equation.

(iii) Solve the equation 3 cos 2θ = 1 using the normal technique for 0 ≤ θ ≤ π (answer to 3 decimal places) and compare your answers with those in part (ii).

  34. (i) Sketch y = tan πx for 0 ≤ x ≤ 2.

(ii) On the same diagram, sketch y = 1 - x.

(iii) Hence determine the number of solutions to the equation tan πx = 1 - x for 0 ≤ x ≤ 2.

  35. (i) Sketch the graph of y = sin 2x for 0 ≤ x ≤ π using relevant sub-intervals.

(ii) Hence find the solutions to √2sin 2x > 1 for
0 ≤ x ≤ π.

  36. (i) Draw a neat sketch of the curve y = 3sin 2x for
0 ≤ x ≤ 2π.

(ii) On the same diagram, sketch y = 1 - cos x for
0 ≤ x ≤ 2π.

(iii) Hence determine the number of solutions the equation 3 sin 2x + cos x = 1 will have in the given domain.