Question

The value of $\sin 600^{\circ }\cos 330^{\circ }+\cos 120^{\circ }\sin 150^{\circ }$ is

• A. $-1$
• B. $1$
• C. $\frac{1}{\sqrt{2}}$
• D. $\frac{\sqrt{3}}{2}$

Answer 1

Answer: (A)

$\sin 600^{\circ }\cos 330^{\circ }+\cos 120^{\circ }\sin 150^{\circ }$
$=-\sin 60^{\circ }\cos 30^{\circ }-\sin 30^{\circ }\cos 60^{\circ }$
$=-\left\{\sin \left(60^{\circ }+30^{\circ }\right)\right\}=-1$