الفهرس | Only 14 pages are availabe for public view |
Abstract A vast variety of the simple and direct methods to find analytic .solutions of nonlinear partial differential equations (PDEs) has been developed. We concern in our work with certain methods: <U+2022> Homogeneous balance method (HBM). <U+2022> Tanh method . <U+2022> Modified tanh method. <U+2022> Extended tanh method. <U+2022> Sinecosine method. <U+2022> Hyperbolic function method. Although the types of solutions of these methods are different; there is some relation between them since the stem of all these methods is the HBM. The main objectives of this thesis is to obtain all these solutions in unified way. The thesis is organized as follows. Chapter one contains a brief introduction to the PDEs, definition and properties of solitons and the main objectives of this thesis. Chapter two presents the HBM. The fisher equation and Kuramoto <U+2013> Sivashinsky (KS) equation are chosen to illustrate this method. Chapter three introduce three approaches to construct exact solution of PDEs. The tanh method, the modified tanh method and the extended tanh method. In chapter four, we explain how to use the sinecosine method and hyperbolic function method to solve a nonlinear PDE. In chapter five, we introduce the main results of this thesis. Firstly, we prove a theorem which can be app;ied in certain cases to simplify the set of algebraic equations obtained in the course of solution of some nonlinear PDEs using the algebraic methods. Then, a clear picture of the relations between the methods mentiond above is observed. Finally, a modification of the HBM is proposed to enlarge the set of solutions solutions obtained by this method to include all types solutions obtained by the above mentioned method. In chapter six, the traffic flow problem on a highway is formulated in terms of Burgers? equation. The modified HBM is applied to solve this equation. Chapter seven is divided into two sections: conclution and future work. The thesis is concluded with the references used in this research. |