Sin 2п/5 cos 7п/30 - sin 2п/5 cos 7п/30

Question

Sin 2п/5 cos 7п/30 - sin 2п/5 cos 7п/30

Answer 1

Sin 2п/5 cos 7п/30 - sin 2п/5 cos 7п/30= sin( 2П\5-7п/30)= sin(5П\30)=sin П\6= 0,5