Abstract
A direct approach to exact solutions of nonlinear partial differential equations is proposed. by using rational function transformations. The new method provides a more systematical and convenient handling of the solution process of nonlinear equations, unifying the tanh-function type methods, the homogeneous balance method, the exp-function method, the mapping method, and the F-expansion type methods. Its key point is to search for rational solutions to variable-coefficient ordinary differential equations transformed from given partial differential equations. As an application, the construction problem of exact solutions to the 3 + 1 dimensional Jimbo-Miwa equation is treated, together with a Backlund transformation. (C) 2009 Elsevier Ltd. All rights reserved.