利用均值不等式求最值要注意以下三点：(1)“正”指均值不等式成立的前提条件是a,b∈R~+,即a,b为正数；(2)“定”指用均值不等式时需要通过补项、拆项、平衡系数等方法凑成和(或积)为定值；(3)“等”指用均值不等式求最值时,一定 The use of the mean inequality to find the maximum value should pay attention to the following three points: (1) “positive” means that the mean value inequality holds the precondition that a, b ∈ R ~ +, that is, a, b is a positive number; (2) “fixed” refers to In the mean inequality, it is necessary to make (or product) a fixed value by means of complements, deconstructions, balance coefficients, etc.; (3) “Equivalence” refers to the use of the mean inequality to determine the maximum value.