Show that `aCos^2[A/2]+ bCos^2[B/2]+ c Cos^2[C/2]=s+D/R`

Show that a cos^(2)[(A)/(2)]+b cos^(2)[(B)/(2)]+c cos^(2)[(C)/(2)]=s+(D)/(R)

Prove that a cos^(2)(A/2)+b cos^(2)(B/2)+c cos^(2)(C/2)=s+(Delta)/(R)

If A+B+C= pi/2 , show that : cos^2 A + cos^2 B + cos^2 C = 2 + 2 sinA sinB sinC .

Show that, 4 R r cos ""A/2cos ""B/2 cos ""C/2 =Delta

In Delta ABC prove that cos^(2)((A)/(2))+cos^(2)((B)/(2))+cos^(2)((C)/(2))=2+(r)/(2R)

If A+B+C=2S , prove that : cos^2 S + cos^2 (S-A) + cos^2 (S-B) + cos^2 (S-C) = 2+2cosA cosB cosC .

If A+B+C=pi , prove that cos 2A +cos 2B +cos 2C=-1-4cos A cos Bcos C.

Show that : cos A+ cosB + cosC+ cos(A+B+C) = 4cos""(B+C)/(2)cos""(C+A)/(2)cos""(A+B)/(2) .

If A+B+C = pi , show that |["sin"^(2)A, "sin A cos A", "cos"^(2)A],["sin"^(2) B, "sin B cos B", "cos"^(2)B],["sin"^(2)C, "sin C cos C", "cos"^(2)C]| =-"sin (A-B)"sin"(B-C)"sin"(C-A)"

In DeltaABC , prove that: (bcos^(2)C)/2+(c cos^(2)B)/2=s