有些分式对称不等式的证明往往要通过构造均值不等式去分母来证明,那么如何构造适当的均值不等式?关键在于凑项去分母.一般需凑的项要与待证不等式右边项结构相同.每个同类项要凑多少项可以通过待定系数法来确定.下面举两例加以说明. The proof of some fractional symmetric inequalities is often proved by constructing the mean inequality to denominator, then how to construct a proper mean inequality? The key is to make up the term to the denominator. The items that are generally required to be mined are the same as the structure of the right side of the indifference inequality. How many items of the same type can be summed up can be determined by the undetermined coefficient method. Here are two examples to illustrate.