Q. The value of $\sin{50{^\circ} - \sin{70{^\circ} + \sin{10{^\circ}}}}$ is
A) 0
B) 1
C) $\frac{1}{2}$
D) $\frac{1}{\sqrt{2}}$
Explanation
(a)
$\sin{50{^\circ} + \sin{10{^\circ} - \sin{70{^\circ}}}}$
$= 2\sin{30{^\circ}\cos{20{^\circ} - \cos{20{^\circ}}}}$
$= \cos{20{^\circ}\left( 2 \times \frac{1}{2} - 1 \right) = 0}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.