Prove that Sin (4pi/9 + 7). Cos (pi/9 + 7) - Cos (4pi/9 + 7). Sin (pi/9 + 7) = Root3/2 Share with your friends Share 0 Nazmin Hussain answered this Here is the proof :- (Open the image👇) 6 View Full Answer Simranpreet Singh answered this Wish it may helps you!!! 2