“…We prove the following theorems: Theorem: If R 〉 0, F 〉 0, T A 〉 0, σ r ≥ 0 and σ i ≠ 0 then the necessary condition for the existence of non-trivial solution (W, Θ, Z) of equations (16), (17) and (18) (20) Taking complex conjugate on both sides of equation (18), we get (21) Therefore, using (21), we get (22) Also taking complex conjugate on both sides of equation (17) …”