topic badge
Australia
10&10a

7.04 Trigonometric equations

Worksheet
Trigonometric equations
1

Find the size of the acute angle \theta in the following equations:

a

\cos \theta = \dfrac{1}{2}

b

\sin \theta = \dfrac{1}{\sqrt{2}}

c

\tan \theta = \sqrt{3}

d

\sin \theta = \dfrac{\sqrt{3}}{2}

e

\sin \theta = \dfrac{1}{2}

f

\tan \theta = \dfrac{1}{\sqrt{3}}

2

Solve the following equations for 0\degree \leq x \leq 90\degree:

a

\tan x = 1

b

\sin x = \dfrac{1}{2}

c

2 \cos x = 1

d

\cos x = \dfrac{\sqrt{3}}{2}

e

\cos x - 1 = 0

f

\sqrt{2} \sin x = 1

g

\sin x - 1 = 0

h

\sin x = \dfrac{\sqrt{3}}{2}

3

Solve the following equations for 0\degree \leq \theta \leq 90\degree:

a

2 \sin \theta = 2 \sqrt{3} \cos \theta

b

\tan \theta = 2 \sqrt{3} - \tan \theta

c

6 \sin \theta - 3 \sqrt{3} = 0

d
4 \cos \theta - 2 \sqrt{3} = 0
4

State whether the following equations have a solution:

a

\cos \theta - 4 = 0

b

9 \tan \theta + 4 = 0

5

State the number of solutions for \theta in the following equations:

a

\cos \theta = - \dfrac{1}{2} for 0 \degree < \theta < 180 \degree

b

\tan \theta = - 1 for 0 \degree < \theta < 90 \degree

c

\sin \theta = - \dfrac{1}{\sqrt{2}} for 0 \degree < \theta < 90 \degree

d

\sin \theta = \dfrac{\sqrt{3}}{2} for 0 \degree < \theta < 180 \degree

6

Solve the following equations for 0\degree \leq x \leq 360\degree:

a

\cos x = \dfrac{1}{2}

b

\sin x = \dfrac{1}{\sqrt{2}}

c

\tan x = \dfrac{1}{\sqrt{3}}

d

\sin x = - \dfrac{1}{\sqrt{2}}

7

Solve the following equations for 0 \degree \leq \theta \leq 360 \degree:

a

\cos \theta = - \dfrac{1}{\sqrt{2}}

b

\cos \theta = 0

c

\sin \theta = 0

d

\cos \theta = -\dfrac{1}{\sqrt{2}}

e

\sin \theta = - \dfrac{\sqrt{3}}{2}

f

\sin \theta = 1

g

\tan \theta = \sqrt{3}

h

\tan \theta = 0

i

\tan \theta = - \dfrac{1}{\sqrt{3}}

8

Solve the following equations for 0 \degree \leq \theta \leq 360 \degree:

a

4 \tan \theta + 2 = - 2

b

8 \cos \theta - 4 = 0

c

2 \cos \theta + 4 = 3

d

8 \sin \theta - 4 \sqrt{2} = 0

9

Find the value of y in the following equations:

a

\dfrac{5}{8} \cos y = \dfrac{5 \sqrt{2}}{16} for 0 \degree < y < 90 \degree

b

\dfrac{6}{2} \sin y = \dfrac{3 \sqrt{3}}{2} for 0 \degree < y < 180 \degree

Non-exact value equations
10
Solve the following equations for 0 \degree \leq \theta \leq 90 \degree to the nearest degree:
a

\cos \theta = 0.7986

b

\sin \theta =0.6428

c

\tan \theta =0.7265

d

\sin \theta = 0.3584

e

\tan \theta = 2.2460

11

Solve the following equations for 0 \degree \leq \theta \leq 360 \degree to the nearest degree:

a

\cos \theta = 0.9063

b

\cos \theta = - 0.7986

c

\sin \theta = - 0.6428

d

\sin \theta = 0.9336

e

\tan \theta = 0.7002

f

\tan \theta = - 0.7265

12

Estimate the solutions of the following equations for 0 \degree \leq x \leq 360 \degree using the graph of y = \sin x below:

30\degree
60\degree
90\degree
120\degree
150\degree
180\degree
210\degree
240\degree
270\degree
300\degree
330\degree
360\degree
x
-1
-0.5
0.5
1
y
a

\sin x = 0.6

b

\sin x = -0.2

c

\sin x = \dfrac{1}{10}

d

\sin x = -0.95

13

Estimate the solutions of the following equations for 0 \degree \leq x \leq 360 \degree using the graph of y = \cos x below:

30\degree
60\degree
90\degree
120\degree
150\degree
180\degree
210\degree
240\degree
270\degree
300\degree
330\degree
360\degree
x
-1
-0.5
0.5
1
y
a

\cos x = 0.1

b

\cos x = -0.2

c

\cos x = \dfrac{1}{4}

d

2 \cos x = -1.2

14

Estimate the solutions of the following equations for 0 \degree \leq x \leq 360 \degree using the graph of y = \tan x below:

30\degree
60\degree
90\degree
120\degree
150\degree
180\degree
210\degree
240\degree
270\degree
300\degree
330\degree
360\degree
x
-5
-4
-3
-2
-1
1
2
3
4
5
y
a

\tan x = 0.5

b

\tan x = -3

c

\tan x = \dfrac{3}{2}

d

2 \tan x = -8

Sign up to access Worksheet
Get full access to our content with a Mathspace account

Outcomes

ACMMG275 (10a)

Solve simple trigonometric equations

What is Mathspace

About Mathspace