In studying the nonlinear electrohydrodynamic stability of solitary wa
ve packets of capillary-gravity waves, in (2+1) dimensions, for dielec
tric fluids, we found that the complex amplitude of the surface elevat
ion can be described by a nonlinear Schrodinger equation which can be
written in the form of a soliton envelope equation. Using the tanh met
hod we get in a very simple way the solitary wave solutions of this eq
uation which we had obtained before by using the Jacobian elliptic fun
ctions.