多元函数的最值问题是近几年来高考的热点话题,此类题目一般涉及知识面较广,常与方程、不等式、三角函数、向量、平面解析几何等知识横向交叉;且处理起来纵向难度较深,技巧性、综合性都很强,因而备受命题者的青睐,成为高考和模考中检验学生思维能力和综合素质的重要素材之一.而有关多元函数的最值问题往往给人形式简单、但难以捉摸的感觉,让学生倍感棘手、束手无策,时常产生“只在此山中, The most value of multivariate function is the hot topic of college entrance examination in recent years. Such topics generally involve a wide range of knowledge, often crosswise with knowledge of equations, inequalities, trigonometric functions, vectors, and plane analytic geometry. Deep, skillful, comprehensive are very strong, and thus favored by the proponents, become the entrance exam and test the students thinking ability and comprehensive quality of the important material one of the most valuable questions about multivariate function often give form Simple, but elusive feel, make students feel thorny, helpless, often produce ”Only in this mountain,