几何学中,形如“1/a+1/b=1/c”的题目,实质上也是比例线段的一种形式。但由于分母都是线段,而分子都是常数,条件与结论的内在联系又不明显,因而同学们感到头疼。本文就一些典型例题的证明,概括了如下几种思考方法,以供探究。 一、结论变形法 1.化去常数,变形为线段之比的形式 In geometry, the shape of “1/a+1/b=1/c” is essentially a form of proportional line segment. However, because the denominator is a line segment, and the molecules are constant, the internal relationship between the conditions and the conclusion is not obvious, so the students feel a headache. This article summarizes the following several ways of thinking for the proof of some typical examples. First, the conclusion of the deformation method 1. Turn constants, deformation into the form of the ratio of segments