近年来,以函数为背景的试题在各地中考卷中屡见不鲜,函数问题在初中数学中占有重要地位,在中考命题中一直是“重头戏”.在这里提供一种解决函数问题的方法——设点法设点法的知识准备.1.常用的辅助线作法:常向x轴或y轴或对称轴作垂线,构造直角三角形.2.常用的解题方法:通常可利用三角形相似(全等)或勾股定理解题. In recent years, it is not uncommon for function-based test questions to be found in middle school exams throughout the world. Function problems occupy an important position in junior high school mathematics and have always been the “main event” in the middle school entrance examinations. The method of point set point knowledge preparation .1 commonly used auxiliary line approach: often to the x-axis or y-axis or axis of symmetry perpendicular to the construction of right-angle triangle .2 commonly used solution to the problem: usually available triangle similar Congruent) or Pythagorean theorem solve the problem.