在△ABC中,R和r分别是△ABC的外接圆半径和内切圆半径,则R≥2r,等号当且仅当△ABC为正三角形时成立,这就是著名的欧拉不等式.如果我们能够找到一个表达式Q使得2r≤Q≤R,那么就称这个表达式Q为欧拉不等式的隔离式,贵刊文[1]、文[2]和文[3]中所给出的隔离式比较复杂,而且有些隔离式也缺乏几何意义,经过研究笔者发现了一个极其简单并且具有明显 In ABC, R and r are the circumcircle and inscribed circle radii of ABC, respectively, then R≥2r, the equals sign if and only if ABC is a positive triangle, which is the famous Euler’s inequality. If We can find an expression Q such that 2r≤Q≤R, then we call this expression Q Euler’s inequality of isolation, the paper [1], article [2] and article [3] given in the isolation More complicated, and some isolation also lack of geometric significance, after research I found an extremely simple and obvious