If xcosθ=ycos[θ-(2π3)]=zcos[θ+(2π3)], then x+y+z is equal to
(0)
We have xcosθ=ycos[θ-(2π3)]=zcos[θ+(2π3)]
Therefore, each ratio is equal to
x+y+zcosθ+cos[θ-(2π3)]+cos[θ+(2π3)]
=x+y+zcosθ+2cosθcos(2π3)
=x+y+z0
⇒x+y+z=0