贵刊文[1]、文[2]、文[3]分别介绍了过点P作圆锥曲线切线的尺规方法,笔者拜读后,受益匪浅.但掩卷深思,却发现上述诸文都有点P在圆锥曲线上的限定,那么,如果不计较点P的位置,也不计较圆锥曲线的种类,只要该曲线客观上存在过点P的切线,能否仅凭借尺规,找到一种过点P且适用于所有 Your article [1], article [2], article [3] respectively introduce the point method that the point P makes the tangent of the conic curve, after the author reads, benefited a lot .However, If the position of the point P is ignored, the type of the conic curve is ignored, so long as the curve objectively has a tangent to the point P, can it be found only by the rule Point P and apply to all