平面几何问题对很多学生来说是比较困难的,当解题过程中要添加辅助线时,他们就更加觉得无从下手了.实际上,添加辅助线是有规律可循的.本文把作辅助线的一些基本原则总结出来,并加以应用,希望对大家有所帮助.1.化归原则所谓的化归,就是在研究和解决有关数学问题时,采用某种方法,将复杂问题通过变换转化为简单问题;将难解的问题通过变换转化为易解的问题;将未解决的问题通过 Plane geometry problems for many students is more difficult, when the problem-solving process to add auxiliary lines, they feel even more impossible to start .In fact, the auxiliary line is a regular follow-up. Summed up some of the basic principles, and to be applied, I hope all of you to help .1 return to the principle of so-called return, that is, in the study and solve the mathematical problems, the use of a method to transform complex problems into Simple questions; transforms difficult questions into easily solved ones; transforms unresolved issues