" 21.If "A,B," Care angles of triangle then prove that "cos A+cos B+cos C=1+4sin(A)/(2)sin(B)/(2)sin(C)/(2)

If A+B+C=pi then prove that cos A+cos B+cos C=1+4sin((A)/(2))*sin((B)/(2))*sin((C)/(2))

If A,B,C are the angles of a triangle then prove that cos A+cos B-cos C=-1+4cos((A)/(2))cos((B)/(2))sin((C)/(2))

If A,B,C are the angles of a triangle then prove that cosA+cosB-cosC=-1+4cos(A/2)cos(B/2)sin(C/2)

If A,B,C are the angles of a triangle then prove that cosA+cosB-cosC=-1+4cos(A/2)cos(B/2)sin(C/2)

If A, B, C are angles of a triangle , prove that cos 2A - cos 2B + cos 2C =1 -4 sin A cos B sin C

If A, B, C are angles of a triangle , prove that cos 2A+cos 2B -cos 2C=1-4 sin A sin B cos C

If A, B, C are angles in a triangle , prove that sin A+ sin B -sin C =4sin. (A)/(2)sin. (B)/(2) cos. (C)/(2)

If A + B + C = pi then prove that cos A + cos B + cos C = 1 + 4 sin(A/2) .sin(B/2).sin(C/2)

If A + B + C = pi , prove that cos A + cos B + cos C= 1 + 4 sin(A/2) sin(B/2) sin(C/2)