此篇論文的主要工作是介紹當我們給定一個微分方程時，我們將利用 Lie symmetry 這套工具來簡化所給之微分方程。而我們將以三個重要的例子來說明如何找到合適的 Lie symmetry。 In this work a general systematic method based on the point symmetry theory of Lie group to find an invariant transformation of a given differential equation will be introduced. A proper transformation can reduce the order, simplify the complexity, or even find the exactly solution of differential equations. Hence to find a good transformation is crucial. Three typical important examples will be illustrated how to find a suitable transformation.
