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

If A, B , C =pi, then prove that cos ^(2). (A)/(2)+ cos^(2). (C)/(2)- cos^(2). (C)/(2)=2(cos. (A)/(2) cos. (B)/(2)sin. (C)/(2))

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

If A+B+C=pi then prove that cos^(2)((A)/(2))+cos^(2)((B)/(2))-cos^(2)((C)/(2))=2cos((A)/(2))cos((B)/(2))sin((C)/(2))

If A+B+C=180^0 , prove that : cos^2( A/2) + cos^2( B/2) + cos^2(C/2) = 2+2 sin(A/2) sin( B/2) sin( C/2)

If A+B+C=180^0 , prove that : cos^2( A/2) + cos^2( B/2) + cos^2(C/2) = 2+2 sin(A/2) sin( B/2) sin( C/2)

If A+B+C=pi then prove that cos^2 (A/2)+cos^2 (B/2)-cos^2 (C/2)=2cos(A/2)cos(B/2)sin(C/2)

cos A + cos B + cos C = 1 + 4sin ((A) / (2)) sin ((B) / (2)) sin ((C) / (2))

If A+B+C=2 pi, then prove that cos^(2)B+cos^(2)C-sin^(2)A=2cos A cos B cos C

If A+B+C=(3pi)/(2) , prove that cos ^(2)A+ cos ^(2) B- cos ^(2)C=-2 cos A cos B sin C.

Prove that (cos^(2)A-sin^(2)B)+1-cos^(2)C