20.4 Exact trigonometric values — Practise
Work independently. Estimate where useful, show your method, and check units. In the mixed questions, choose the method and give a reason.
- Work out exactly: sin 30°.
- Work out exactly: cos 30°.
- Work out exactly: tan 45°.
- Work out exactly: sin 60° + cos 60°.
- Work out exactly: tan 30° × tan 60°.
- Work out exactly: 2 cos 60° + sin 90°.
- Work out exactly: sin 45° × cos 45°.
- Work out exactly: sin² 30° + cos² 30°.
Answers and concise solutions
1. Question 1
Answer: 1/2
2. Question 2
Answer: √3/2
3. Question 3
Answer: 1
4. Question 4
Answer: (√3 + 1)/2
5. Question 5
Answer: 1
6. Question 6
Answer: 2
7. Question 7
Answer: 1/2
8. Question 8
Answer: 1