与线段有关的分类讨论问题,主要有以下七种类型:一是由于点的位置不确定而进行的分类;二是由于三角形一边上的高在形内(外)不确定而进行的分类;三是相似三角 There are seven main types of discussion about line classification: one is the classification due to the uncertainty of the location of the point; the other is the classification due to the high in-shape (outside) uncertainty on one side of the triangle; the third Is similar to the triangle