# $\sin A+ \sin B= \sqrt {3} (\cos B- \cos A)$ => $\sin 3A+ \sin 3B$ is equal to

$\begin {array} {1 1} (a)\;0 & \quad (b)\;1 \\ (c)\;1 & \quad (d)\;-1 \end {array}$

(a) 0
answered Nov 7, 2013 by