Multiple new travelling wave solutions to the shallow long wave approximate equations with variable coefficients

Six types of new exact solutions to the Riccati equation associated with extended tanh-function method are presented and used uniformly for constructing multiple travelling wave solutions to nonlinear evolution equations. For illustration, multiple new travelling wave solutions to the shallow long wave approximate equations with variable coefficients are obtained. The method is straightforward, concise, and it also applied to other nonlinear evolution equations in mathematical physics.