【摘要】 运用高等几何中二次曲线的度量理论证明了椭圆的一个基本性质:椭圆上的任一点到两焦点的距离之和为定长;反之满足这一条件的点所构成的二阶曲线一定是椭圆.更多还原

【Abstract】 With a framework of quadratic curve’ metric theory,anelementry nature of ellipse is proved:The sum of the distance from any point of ellipse to the two focuses is fixed-length.On the other hand,the curve of second order composed with those points accord with above-mentioned factor is sure to an ellipse.更多还原