求无理函数的最值常见的方法有代数换元法、三角换元法、导数法等.但是有一些无理函数因其解析式结构的特殊性,用以上常规的方法不易求其最值,若能仔细分析无理函数解析式的结构特点,数形结合,构造出相应的平面解析几何模型,利用其“形”的特征,可转化为求平面解析几何模型(曲 Seeking unreasonable functions of the most common methods algebraic metamorphosis, trigonometry, derivatives, etc. However, there are some irrational function because of the particularity of its analytical structure, the above conventional method is not easy to find the most value, if We can carefully analyze the structural features of the analytic formula of unreasonable functions, and combine the several shapes to construct the corresponding plane analytical geometry model. By using its “shape” characteristics, it can be transformed into the plane analytical geometry model