`cos2B+cos2A-cos2C=1-4sinAsinBcosC`

In DeltaABC , prove that: cos2A+cos2B-cos2C=1-4sinAsinBcosC

If A+B+C=pi , prove that : cos2A+cos2B-cos2C=1-4sinA sinB cosC

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

If A+B+C = pi , prove that : cos2A +cos2B +cos2C =-1-4cosAcosBcosC .

If A+B+C = pi , prove that : cos2A-cos2B -cos2C = -1+4cosAsinBsinC

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=180^(@) then cos2A+cos2B+cos2C=1-4cos A cos B cos C 2.If A+B+C=0 then cos A+cos B+cos C=-1+4(cos A)/(2)(cos B)/(2)(cos C)/(2)

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

If A+B+C=270^(@), then cos2A+cos2B+cos2C+4sin A sin B sin C=

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