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对称问题是高考热点,包括点关于点的对称、直线关于点的对称、点关于直线的对称、直线关于直线的对称,我们应熟练掌握。一、点P(x1,y1)关于点C(a,b)的对称点的坐标是(2a-x1,2b-y1)。点关于点的对称实质是中点坐标公式的应用。[例]已知点A(4,5),B(2,3),试求A点关于B点的对称点A’的坐标。解:设A’点坐标为(x,y),由中点坐标公式有:
The symmetry problem is the college entrance examination hotspot, which includes symmetry about the point, the symmetry of the line about the point, the symmetry of the point about the line, and the symmetry of the line about the line. We should be familiar with it. 1. The coordinates of point P(x1, y1) with respect to the point of symmetry of point C(a, b) are (2a-x1, 2b-y1). The point of symmetry about the point is the application of the midpoint coordinate formula. [Example] Know the points A(4,5) and B(2,3) and try to find the coordinates of point A about the symmetry point A’ of point B. Solution: Let A’s coordinates be (x,y), and the midpoint coordinate formulas are: