Most recently, Wazwaz [5] established a necessary condition that is essentially needed to ensure the appearance of ``noise terms'' in the inhomogeneous
equations. The necessary condition for the ``noise terms'' to appear in the
components u0 and u1 is that the exact solution u
among other terms. In addition, the remaining non-canceled terms of u0 must
satisfy the equation under discussion. It is not true that ``noise terms'' appear
for all inhomogeneous equations as indicated in [3]. The newly necessary
condition developed in [5] was formally proved and tested to demonstrate the
power of the ``noise terms'' when these terms appear in the components u0 and
u1. For more details see [5,6].
x must appear as part of u0