x = ycos 2Ï€/3 = zcos 4Ï€/3
implies, x = -y/2 = -z/2
-2x = y = z
Now, xy + yz + xz
= x (-2x) + (-2x)(-2x) + x (-2x)
= -2x2 + 4x2 -2x2
= 0
x = ycos 2Ï€/3 = zcos 4Ï€/3
implies, x = -y/2 = -z/2
-2x = y = z
Now, xy + yz + xz
= x (-2x) + (-2x)(-2x) + x (-2x)
= -2x2 + 4x2 -2x2
= 0