七、有关椭圆的作图 1.已知椭圆的长短轴作椭圆如图16,给定椭圆的长轴AB、短轴CD。以AB为直径作一个圆交CD的延长线于点C_1、D_1。从而构成了以AB为亲似轴,C_1、C为一对对应点的正亲似对应。在圆上任取一点M_1,求其对应点M的方法有二。方法1:连C_1M_1交AB于点P_0,连P_0C,作M_1M_0||C_1C交P_0C于占M即为所求。 Seven, the oval mapping 1. Known oval long axis for the ellipse as shown in Figure 16, given the oval long axis AB, short axis CD. Take AB as the diameter of a circle to pay CD extension line at points C_1, D_1. Thus forming a pro-like axis AB, C_1, C for a corresponding point of positive relatives correspondence. There are two ways to take a point M_1 on a circle and find its corresponding point M. Method 1: Even C_1M_1 to pay AB point P_0, with P_0C, for M_1M_0 || C_1C pay P_0C accounted for M is required.