｜｜ａ｜－｜ｂ｜｜≤｜ａ＋ｂ｜≤｜ａ｜＋｜ｂ｜是中学数学中的一个基本不等式．当ａ、ｂ∈Ｒ时，我们称其为绝对值不等式，右端等号当且仅当ａｂ≥０时成立，左端等号当且仅当ａｂ≤０时成立；当ａ、ｂ∈Ｃ时，我们又称其为复数模的不等式，右端等号当且仅当ａ＝ｋｂ（... ||a|-|b||≤|a+b|≤|a|+|b| is a basic inequality in middle school mathematics. When a, b ∈ R, we call it an absolute value inequality, the right-side equal sign holds if and only if ab ≥ 0, and the left-end equal sign holds if and only if ab ≤ 0; when a, b ∈ C, We also call it the complex modulus inequality, the right equal sign if and only if a=kb(...