" Frove that "cos^(2)A+cos^(2)B-cos^(2)C=1-2sin A sin B cos C

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

If A + B + C =180^@ , prove that : cos^2 A+ cos^2 B-cos^2 C= 1-2 sin A sin B cos C .

Prove that in triangle ABC,cos^(2)A+cos^(2)B-cos^(2)C=1-2sin A sin B cos 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=(3pi)/(2) , prove that cos ^(2)A+ cos ^(2) B- cos ^(2)C=-2 cos A cos B sin C.

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

If A + B + C =pi/2 , prove that : cos^2 A +cos^2 B+cos^2 C= 2+2 sin A sin B sin C .

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

cos2B + cos2A-cos2C = 1-4sin A sin B cos C

If A+B+C= (pi)/(2) ,prove that: (i) cos^(2)A+cos^(2)B+cos^(2)C=2+2"sin"A "sin"B "sin"C (ii) "sin"^(2)+"sin"^(2)B+"sin"^(2)C=1-2 "sin"A sin B sin C .