平面曲线的切线

平面解析几何对“求过二次曲线外的点所引曲线切线的方程”的问题,未给出一般的方法和公式。本文借助简单的微分运算对这一问题给出一种解决办法,并对一般的平面曲线的切线作了初步讨论。

The Tangent of a Plane Curve

The problem of attaining the tangent equation of a certain point on a quadratic curve is basically solved in plane analytical geometry. But there hasn't been a general solution to the problem of attaining the tangent equation of the curve that is deduced from a point outside a quadratic curve , and a general appropriate formula is not mentioned either.In this paper , by means of simple differential operations, a perfect solution to the second problem stated above is presented . And the problem of attaining the tangent of a general plane curve is discussed elementarily.