Now let x 0 be some random point (where both wave functions are defined) and set: c 1 = ψ ψ 2 ( x 0 , 0 ) a and c 2 = − − ψ ψ 1 ( x 0 , 0 ) a with a = | ψ ψ 1 ( x 0 , 0 ) | 2 + | ψ ψ 2 ( x 0 , 0 ) | 2 > 0 (according to the premise no nodes).