In triangle ABC, prove that `cos .(A)/(2)+cos.(B)/(2)+cos. (C)/(2) =4 cos .(pi-A)/(4)cos. (pi-B)/(4) cos.(pi-C)/(4)`

In Delta ABC , prove that cos. (A)/(2)+cos. (B)/(2) - cos .(C)/(2)=4cos .(pi+A)/(4) cos. (pi+B)/(4) cos. (pi-C)/(4)

In triangle ABC , prove that sin .(A)/(2)+ sin. (B)/(2) -sin. (C)/(2)=-1+4 cos.(pi-A)/(4)cos. (pi-B)/(4)sin. (pi-C)/(4)

In triangle ABC, prove that cos(A/2)+cos(B/2)+cos(C/2)=4cos(pi-A)/4cos(pi-B)/4cos(pi-C)/4

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

If A +B+C = 180^circ , prove that cos A/2+ cos B/2 +cos C/2 = 4cos (pi-A)/4 * cos(pi-B)/4 cos(pi-C)/4

In any triangle ABC, prove that : cos frac (A)(2) +cos frac (B)(2)+cos frac (C)(2)= 4 cos frac (pi-A)(4) cos frac (pi-B)(4) cos frac (pi-C)(4) .

cos ((A) / (2)) + cos ((B) / (2)) - cos ((C) / (2)) = 4cos ((pi + A) / (4)) cos ((pi + B) / (4)) cos ((pi-c) / (4))

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

In triangle ABC, prove that sin((A)/(2))+sin((B)/(2))+sin((C)/(2))<=(3)/(2) Hence,deduce that cos((pi+A)/(4))cos((pi+B)/(4))cos((pi+C)/(4))<=(1)/(8)

If A+B+C=180^(@) then prove the following: "cos"A/2+"cos"B/2+"cos"C/2 =4cos((pi-A)/4)cos((pi-B)/4)cos((pi-C)/4)