用基本不等式求函数最值是高中数学的一个重要方法之一.众所周知,在应用其求最值时,需考虑三个前提条件:“一正、二定、三相等”.当有些题目的条件不满足这些要求时,这就需要我们创设条件,进行合理配凑,再用基本不等式求出最值.下面举几例,抛砖引玉.一、配凑“正”例1已知x<5/4,求函数f(x)=4x-2 Using basic inequalities to find the value of a function is one of the most important ways in high school mathematics.It is well known that there are three prerequisites to be considered when applying its maximum value: "one positive, two definite, three equal Of the conditions do not meet these requirements, which requires us to create the conditions for a reasonable fit together, and then use the basic inequality find the most value. Here are a few examples to start with. <5/4, find the function f (x) = 4x-2