What is (p+q+r) equal to?
Consider the following for the three (03) items that follow : Let p=\sin 35^{\circ}, q=\sin 25^{\circ} and r=\sin(-95^{\circ}).
- A. -1
- B. 0 ✓
- C. 2 \sin 5^{\circ}
- D. 2 \cos 5^{\circ}
Correct Answer: B. 0
Explanation
p+q = \sin 35^{\circ} + \sin 25^{\circ} = 2\sin 30^{\circ}\cos 5^{\circ} = \cos 5^{\circ}. And r = \sin(-95^{\circ}) = -\sin 95^{\circ} = -\cos 5^{\circ}. Thus p+q+r = \cos 5^{\circ} - \cos 5^{\circ} = 0.