文[1]给出了关于抛物线的弦对顶点张直角的一个充要条件:设直线l与抛物线y2=2px相交于A、B两点,则OA⊥OB(O是坐标原点)的充要条件是直线l过定点(2p,0).文[1]还对有心圆锥曲线的弦对对称中心张直角进行了研究并获得了一组结论.本文给出关于有心圆锥曲线的弦对顶点张直角的充要条 The paper [1] gives a necessary and sufficient condition for the orthogonal angle of the vertex pair of the parabola: If the line l and the parabola y2=2px intersect at two points A and B, then OA⊥OB (O is the coordinate origin) The condition is that the straight line l is over the fixed point (2p, 0). The paper [1] also studied the symmetry central straight angle of a string pair with a concentric conic curve and obtained a set of conclusions. Right angles