读了《数学通报》2 0 0 4年第 2期《构造向量证三元分式不等式》一文[1] ,笔者很叹服作者那种高超的“构造”技巧 ,作为工具的向量不等式｜a｜2 ｜b｜2 ≥ (a·b) 2 (1 )简洁而深刻 ,它是欧几里得空间中的哥西———施瓦兹不等式 .在用它证明分式不等式时 ,关键就是如何恰当地 I read the article “Mathematical Bulletin” No. 2, 2004, “Constructing a Vector Variance Triplex inequality” article [1], the author is very impressed by the author’s superb “construction” skills, as a vector of tools inequality | a | 2 | b | 2 ≥ (a · b) 2 (1) Concise and profound, it is the Coogee-Schwarz inequality in Euclidean space. When using it to prove a fractional inequality, the key is Properly