Half Angle Formula of `cos (A/2) ,cos (B/2), cos (C/2)`

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

Prove that : (sin 2A+sin 2B + sin 2C)/(cos A + cos B + cos C-1) = 8 cos(A/2) cos( B/2) cos( C/2)

If ABC is a right angled triangle, then the value of (cos ^(2)A +cos ^(2) B+ cos ^(2)C) is -

If A+B+C=pi then prove cos( (A)/2) cos( (B-C)/2) + cos( B/2) cos((C-A)/2) + cos( C/2) cos( (A-B)/2) = sinA +sinB+sinC

If A+C+B=180, then the value of (cos ^(2) A+ cos ^(2) B +cos ^(2) C-2 cos A cos B cos C) is-

If A + B + C = 180^(@) , prove that cos A + cos B - cos C = -1 + 4 cos (A)/(2) cos"" (B)/(2) sin"" (C )/(2)

In a triangle ABC If ( 2 cos A)/a + ( cos B)/b + (2 cos C)/c = a/(bc) + b/(ca) , find the angle A.

If in a triangle ABC, 2 (cos A)/(a) + (cos B)/(b) +2 (cos C)/(c) = (a)/(bc) + b/(ca) then the value of the angle A is

In a triangle ABC If (2cos A)/(a)+(cos B)/(b)+(2cos C)/(c)=(a)/(bc)+(b)/(ca) find the angle A .

If in a triangle ABC, 2 (cos A)/(a) +(cos B)/(b)+2(cos C)/c=(a)/(bc)+b/(ca) then the value of the angle A is