Question:
What is (p + q + r) equal to?
What is (p + q + r) equal to?
Options:
- a) -1
- b) 0
- c) 2sin 5°
- d) 2cos 5°
- a) -1
- b) 0
- c) 2sin 5°
- d) 2cos 5°
correct answer : b)
Explanation:
p + q + r = sin 35° + sin 25° +
sin(-95°)
= sin 35° + sin 25° – sin 95°
= sin 35° + 2 cos 60°.sin(-35°)
= sin 35° – 2 ×
1
2
sin 35° = 0
p + q + r = sin 35° + sin 25° +
sin(-95°)
= sin 35° + sin 25° – sin 95°
= sin 35° + 2 cos 60°.sin(-35°)
= sin 35° – 2 ×
1
2
sin 35° = 0