最值原理:设m是常数. (1)若变量y≥m恒成立,且其等号会成立,则y的最小值是m; (2)若变量y≤m恒成立,且其等号会成立,则y的最大值是m. 灵活运用最值原理给解题带来简便,由于课本没有明确描述此原理,因此许多人对它的认识很模糊,以至不能很好地运用它,因此最 The principle of maximum value: Let m be a constant. (1) If the variable y ≥ m is constant and its equal sign holds, the minimum value of y is m; (2) If the variable y ≤ m is constant, and its equal sign Will be established, then the maximum value of y is m. The use of the principle of maximum value to solve the problem is simple, because the textbook does not explicitly describe this principle, so many people’s understanding of it is very vague, so it can not be used properly, so most