quadratic curve equation的意思|示意

The problem of attaining the tangent equation of a certain point on a quadratic curve is basically solved in plane analytical geometry.

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。

The analog equation between soil erosion resistance index and time is quadratic power function curve, whose correlation coefficient is above 0.9.

不同林分的抗蚀指数与时间的动态模拟关系为二次幂函数曲线，相关系数0.9以上。