《中学生数学》2003年2月上期第25页刊文《巧用a/(b~2)≥2/b-1/a证明不等式》,在该文中列举了8个例题说明了a/(b~2)≥2/b-1/a的应用.读后颇受启发,笔者联想到新教材增加了向量的内容,其中两个向量的数量积有一性质:a~→·b~→≤|a~→|·|b~→|.运用这一性质证明不等式问题,给 “High school students mathematics” in February 2003 the previous page 25 of the article “clever use of a / (b ~ 2) ≥2 / b-1 / a to prove inequalities”, the article lists eight examples of a / (b ~ 2) ≥2 / b-1 / a. After reading quite inspired, I think of the new textbook to increase the content of the vector, in which the number of two vector product has a property: a ~ → · b ~ → ≤ | a ~ → | · | b ~ → |. Use this property to prove the inequality problem