二次根式的化简常用分母有理化的方法,但用这种方法化简较复杂的二次根式时,常会使你陷入“山重水复疑无路”的困境.若巧用换元法,则会出现“柳暗花明又一村”的景象.下面试举例说明.例1化简1+3(2~(1/2))-2(3~(1/2) Simplification of secondary roots is a common method for rationalization of denominators. However, when this method is used to simplify the more complex secondary roots, you often fall into the predicament of “reinventing mountains and water”. If you use the substitution method, Then there will be a scene of “Yao Ming Hua Ming You Cun”. Here is an example to illustrate. Example 1 Simplification 1+3 (2~(1/2))-2(3~(1/2)