Bright and dark solitons for a generalized Korteweg-de Vries-modified Korteweg-de Vries equation with high-order nonlinear terms and time-dependent coefficients

We consider a generalized Korteweg-de Vries-modified Korteweg-de Vries (KdV-mKdV) equation with high-order nonlinear terms and time-dependent coefficients. Bright and dark soliton solutions are obtained by means of the solitary wave ansatz method. The physical parameters in the soliton solutions are obtained as functions of the varying model coefficients. Parametric conditions for the existence of envelope solitons are given. In view of the analysis, we see that the method used is an efficient way to construct exact soliton solutions for such a generalized version of the KdV-mKdV equation with time-dependent coefficients and high-order nonlinear terms.