A+B+C=180^(@)rArr cos2A+cos2B+cos2C=

A+B+C=180^(@),cos2A+cos2B+cos2C=

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)

A+B+C=180^(@)rArr SecA[cos B cos C-sin B sin C]

If A+B+C=180^(@) , then (cos2A+cos2B+cos2C+1)/(cos A cos B cos C)

A+B+C=180^(@)rArr Cosec A[sin B cos C+cos B sin c]=

If A+B+C=180^(@) then cos A+cos B-cosC=

If A+B+C=90^(@) then (cos2A+cos2B+cos2C-1)/(sin A sin B sin C)=

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

In a /_ABC,sin^(4)A+sin^(4)B+sin^(4)C=(3)/(2)+2cos A cos B cos C+(1)/(2)cos2A cos2B cos2C

If A+B+C=180^(@) then cos A+cos B-cos C=