Evaluate : sin 7pi/12 . cos pi/4 - cos 7pi/12 . sin pi/4 Share with your friends Share 5 Rishabh Mittal answered this We know , sin A-B=sin A cos B - Cos A Sin BTherefore ,sin 7π12 cos π4 - cos 7π12 sin π4=sin 7π12-π4=sin 7π-3π12=sin 4π12=sin π3=32 ANS... 12 View Full Answer