2011年安徽高考理科数学试卷第19题是一个二元不等式的证明问题,很多同学不能适应.其实,作为研究函数的重要工具——导数,同学们是相当熟悉的,用导数解决一元不等式问题是一种常见的题型,而用导数处理二元不等式的问题没有引起人们的重视.本题若用导数证明就省去繁琐的恒等变形,显得亲切自然.用导数研究二元不等式问题常见如下三种类型.一、貌似二元不等式,其实就是一元函数 In fact, as an important tool of research function - derivative, students are very familiar with the derivative to solve the problem of univariate inequality is A common problem type, and the use of derivatives to deal with the problem of binary inequality has not attracted the attention of the people.If the derivative of the problem with the proof of omission cumbersome isomorphic, appear to be kind and natural.Using the derivative of the binary inequality problems are common as follows First, the seemingly binary inequality, in fact, is a one-dollar function