If `(x)/( cos theta ) = (y) /( cos (theta - 2pi//3))=(z)/( cos ( theta + 2pi//3))`, then ` x+y+z=`

If (x)/(cos theta)=(y)/(cos(theta-(2pi)/(2)))=(2)/(cos(theta+(2pi)/(3))), then x+y+z=

If (x)/(cos theta)=(y)/(cos(theta-(2 pi)/(3)))=(z)/(cos(theta+(2 pi)/(3))) then x+y+z is (a)1(b)0(c)-1(d) none of these

If x/(costheta)=y/(cos(theta-(2pi)/3))=z/(cos(theta+(2pi)/3)) then x+y+z is

If x cos theta = y cos (theta + (2pi)/(3)) = z cos (theta + (4pi)/(3)) , find the value of xy + yz + zx

If x/(costheta)=y/(cos(theta-(2pi)/3))=z/(cos(theta+(2pi)/3)) then x+y+z is (a)1 (b) 0 (c) -1 (d) none of these