文[1]对椭圆的切线、准线和大圆的直径三者间的联系进行探究,得定理如下:定理1如图1,已知椭圆及其大圆,若QQ′是大圆的直径(异于长轴),分别过Q,Q′作椭圆的两条切线,则这四条切线的另两个交点在椭圆的准线上且关于椭圆的中心对称;反之,若E,E′是椭圆准线上关于其中心对称的两点 In [1], the relationship between the tangent of the ellipse, the line of reference and the diameter of the great circle is explored. The theorem is as follows: Theorem 1 As shown in Figure 1, the ellipse and its great circle are known. If QQ ’is the diameter of the great circle Long axis), respectively, after Q, Q ’for the two tangent of the ellipse, then the other two intersection points of these four tangent lines are symmetrical about the center of the ellipse; on the other hand, if E, E’ On the symmetry of the center of the two points