数学研究中,发现了一些不仅形式优美而且具有重要应用价值的不等式,人们称它们为经典不等式,柯西不等式就属于这样的不等式.柯西不等式在现行高中数学教材选修4-5中系统学习过.柯西不等式在求解最值以及证明不等式中有重要应用,这是众所周知的.本文的视角定位于柯西不等式“等号”成立的条件,列举几例,以飨读者. In mathematics research, we find some inequalities that not only have beautiful forms but also have important application value, which are called classical inequalities and Cauchy inequalities belong to such inequalities. Cauchy inequality has been systematically studied in current high school mathematics textbook elective 4-5 It is well known that the Cauchy inequality has important applications in solving the most value and proving inequalities.The perspective of this paper is based on the condition that the Cauchy inequality “equals ” is established, and a few examples are given to readers.