通过一题多解与一题多变的训练,同学们能够进行多角度的解题思路分析,探讨解题规律和解题方法及技巧,提高数学应用能力,一通百通.下面通过一个习题进行一题多解与一题多变的训练:△ABC是一个三角形的纸片,点D、E分别是△ABC边上的两点.探究(1)如果纸片沿直线DE折叠,使点A′正好落在线段AC上,如图1,则∠BDA′与∠A的关系是_______. Through more than one solution and a variety of training, students can conduct multi-angle analysis of problem-solving ideas to explore the problem-solving law and problem-solving methods and techniques to improve the ability of math applications, a pass through the following exercises △ ABC is a triangular piece of paper, the point D, E are two points on the edge of △ ABC. (1) If the paper folded along the straight line DE, the point A ’Just fall on the line segment AC, as shown in Figure 1, then ∠ BDA’ and ∠ A relationship is _______.