Let A,B and C be three angles such that `cosA+cosB+cosC=0` and if `cosAcosBcosC=lambda(cos3A+cos3B+cos3C)` then find the value of `lambda`

Let A,B and C be three angles such that cos A+cos B+cos C=0 and if cos A cos B cos C=lambda(cos3A+cos3B+cos3C) then find the value of lambda

If three angles A,B,C are such that cos A+ cos B+cos C=0 and if lambda cos A cos B cos C=cos3A+cos3B+cos3C ,then value of lambda is :

If three angles A, B, C are such that cos A+ cos B + cos C = 0 and if lambda cos A cos B cos C = cos 3A + cos 3B + cos 3C , then value of lambda is :

(a+b+c)(cosA+cosB+cosC)

If cosA+cosB+cosC=0, then cos3A+cos3B+cos3C is equal to

If cosA+cosB+cosC=0, then cos3A+cos3B+cos3C is equal to

cos^2 A + cos^2 B +cos^2 C=1+2cosA cosB cosC .

If A+B+C = 180^(@) , then show that cos2B+cos2B+cos2C = -4 cosA.cosB.cosC-1 .

In a triangle ABC, prove that: cos^4A+cos^4B+cos^4C= 3/2 + 2 cosA cosB cosC+ 1/2 cos 2A cos2B cos2C