探究等腰三角形的存在性问题是中考数学的常见题型,这类试题的知识覆盖面较广,综合性较强,题意构思精巧,解题方法灵活,对学生分析问题和解决问题的能力要求比较高.学生初解此类问题时,一般靠直觉画图,凭主观猜测,往往会出现漏解、错解,甚至无从下手等现象.为了更好的帮助学生掌握这一题型的特征与解法,夯实基本问题,便于今后直面更为复杂的情境,针对八 To explore the existence of isosceles triangle is a common problem in the mathematics test, covering a wide range of questions such as knowledge, comprehensive strong, sophisticated ideas, problem-solving method is flexible, students analyze the problem and the ability to solve the problem The students first solution of such problems, the general intuition drawing, with subjective guess, often there will be leakage solution, the wrong solution, or even impossible to start and so on.In order to better help students master the characteristics of the problem and solution , Consolidate the basic problems, to facilitate the face of more complex situations in the future, for eight