If xcosθ=ycosθ−2π3=zcosθ+2π3, then x+y+z=
1
0
-1
2
We have,
xcosθ=ycosθ−2π3=zcosθ+2π3
Therefore, each ratio is equal to
x+y+zcosθ+cosθ−23π+cosθ+2π3=x+y+z0⇒ x+y+z=0