人教版高二数学课本习题6·5第4题是:求证|a|+|b|1+|a|+|b|≥|a+b|1+|a+b|.这是一道看似极其平凡的习题,下面拟从“多证”与“多变”两个不同角度进行一些不平凡的探究,希望能给同学们的学习带来启发.一、一题多证显神韵证法1运用分析法进行证明.要证|a|+|b|1+|a|+|b|≥|a+b|1+ PEP 6 sophomore math textbook exercises 6.5 The fourth question is: Confirmation | a | + | b | 1+ | a | + | b | ≥ | a + b | 1+ | a + b | Like the most ordinary exercises, the following is intended to be from the “multiple” and “changeable” two different perspectives for some extraordinary exploration, hoping to bring to the students’ learning inspiration. 1 Use analytic method to prove. To prove | a | + | b | 1+ | a | + | b | ≥ | a + b | 1+