Grade 11Trigonometry
1) in a triangle ABC prove that cos(A+B)/2=sin C/22) if A, B, C, D be the angles of cycle quadrilateral taken in order prove that Cos(180-A) +cos(180+B)+cos(180+C)-sin(90+D)Pls solve these two fast
1) in a triangle ABC prove that cos(A+B)/2=sin C/2
2) if A, B, C, D be the angles of cycle quadrilateral taken in order prove that
Cos(180-A) +cos(180+B)+cos(180+C)-sin(90+D)
Pls solve these two fast
