等腰三角形是三角形中的一类特殊三角形.它有两边相等.有两个角相等,并且是轴对称图形.下面介绍和这些性质有关的探索性问题.一、探索条件例1如图1,△ABC中,已知AB=AC,要使AD=AE,需要添加的一个条件是____.解析:本题是添加条件开放题,旨在考查同学们的发散思维能力.从说明△ADE是等腰三角形着眼,应附加条件∠ADB=∠AEC或∠BAD=∠CAE,从而可推出∠ADE=∠AED;从说明 An isosceles triangle is a special kind of triangle in a triangle. It has two sides equal. There are two angles equal, and it is an axisymmetric figure. The following describes the exploratory problems related to these properties. First, the exploration condition example 1 is shown in Fig. 1. △ ABC, known as AB = AC, to AD = AE, need to add a condition is ____. Analysis: This question is to add conditional open questions, designed to examine the students’ divergent thinking ability. From the description △ ADE is Waist triangles should focus on conditions ADB=∠AEC or ∠BAD=∠CAE, so that ∠ADE=∠AED can be introduced;