一、方法概述所谓换元法,指的是在解数学题时,把某个式子看成一个整体,用一个变量去代替它,从而使问题得到简化.换元的实质是转化,关键是构造元和设元,理论依据是等量(价)代换,目的是变换研究对象,将问题移至新对象的知识背景中去研究,把分散的条件联系起来,隐含的条件显露出来 First, the method overview The so-called equivalence method, refers to the solution of mathematics problems, the formula as a whole, replace it with a variable, so that the problem is simplified. The essence of the yuan is the transformation, the key is Structural elements and design elements, the theoretical basis is equivalent (price) substitution, the purpose is to transform the research object, the problem is moved to the new object’s knowledge background, the scattered conditions are linked, and the hidden conditions are revealed.