一、转化方法任何三角形总存在内切圆。为此,将三角形三边a、b、c,施行如下变换(如图): (*){a=y+z,b=z+x,c=x+y,就可以把关于三角形各元素的不等式转化成关于正数x、y、z的代数不等式。即 (i)对任何三角形不等式F(a,b,c)≥0,有 First, the transformation method There is always an inscribed circle in any triangle. To do this, apply the following transformations to the triangle’s three sides a, b, and c (as shown in the figure): (*) {a=y+z,b=z+x,c=x+y, you can put elements about the triangle The inequality is transformed into an algebraic inequality about the positive x,y,z. (i) For any triangle inequality F(a,b,c) ≥ 0, there is