近几年来,初中数学中的动点问题是中考命题的“热点”问题。这类题型不仅涉及知识点多,而且能将几何知识和代数知识紧密结合。解决这类的问题的关键是确定变化和不变的元素,正确建立已知和未知的关系,把握运动规律,抓住特殊的位置,做到动中有静,以一般见特殊。例题:在边长为4cm的正方形ABCD中,动点P从点A出发,以2cm/s的速度,沿正方形的边经A-B-C-D到达点D。设运 In recent years, the problem of moving point in junior middle school mathematics is the “hot spot” issue of the senior high school entrance examination. Such questions not only involves more knowledge, but also the geometric knowledge and knowledge of algebra closely. The key to solving this kind of problem is to identify the elements of change and invariance, to correctly establish the relationship between known and unknown, to grasp the law of movement, to grasp the special position, and to make sure that there is something static in the movement. Generally, it is special. Example: In a square ABCD with a side length of 4 cm, the moving point P starts from the point A and reaches the point D along the square A-B-C-D at a speed of 2 cm / s. Set transportation