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我们知道,在平面直角坐标系中,如果位似变换是以坐标原点为位似中心且位似比为k,那么位似图形对应点的坐标的比为±k.而当位似图形的位似中心不在坐标原点时,位似变换后的图形的点的坐标又有怎样的变化规律呢?下面举例说明.例1如图1,ABC中,A,B两个顶点在x轴的上方,点C的坐标是(-1,0).以点C为位似中心,在x轴的下方作ABC的位似图形,并把ABC的边长放大到原来的2倍,记所得的像是A’B’C.设点B的对应点B’的坐标
We know that in a planar Cartesian coordinate system, if the bitmap transformation takes the origin of the coordinates as a bit-centered and the bit-to-bit ratio k, then the ratio of the coordinates of the bitmap-like points is ± k, and when bit-like bit Like the center is not at the origin of the coordinates, bitmap-like graphics after the point of the coordinates of how the law of change? The following example: Figure 1, ABC, A, B two vertices above the x-axis , The coordinate of point C is (-1,0). With point C as the center of the bit, a bitmap of ABC is made below the x-axis, and the side length of ABC is enlarged by two times. Like A’B’C. Set the coordinates of point B ’corresponding to point B’