ON THE PROBLEM THAT THE AREA OF A CURVE OF SECOND DEGREE WITH ITS TWO TANGENTS IS CONSTANT

In this paper we obtain two conclusions on quadric curves. First, for any quadric curve, the locus of the intersection point of its two arbitrary tangents is still a quadric curve with the same type,if the area enclosed by the two tangent and the original curve is a constant. Secondly, for any two given quadric curves of the same types, the area enclosed by one curve and the two tangents of the curve,whose common point is an arbitrary point of the other curve, is a constant.