Question

The value of $\sin 50^{\circ }-\sin 70^{\circ }+\sin 10^{\circ }$ is equal to

• A. 1
• B. 0
• C. $\frac{1}{2}$
• D. 2

Answer 1

Answer: (B)

$\sin 50^{\circ }+\sin 10^{\circ }-\sin 70^{\circ }$
$2\sin 30^{\circ }\cos 20^{\circ }-\sin 70^{\circ }$
$/2.\frac{1}{/2}\cdot \cos 20^{\circ }-\sin 70^{\circ }$
$\cos 20^{\circ }-\cos \left(90^{\circ }-70^{\circ }\right)=0$