解圆锥曲线线相切问题用判别式法管用吗临洮中学白成明先看下面的例题。例１．（１９９０年全国高考题）设椭圆的中心是坐际原点，长轴在ｘ轴上，离心率是，已知点Ｐ到椭圆的最远距离是，求椭圆的方程，并求椭圆上到点Ｐ的距离等于的点的坐标。解：如图（１），设椭圆的方... Solve Conic Curve Line Tangent Question Using Discriminative Method Does Linyi Middle School Bai Chengming See the following examples first. Example 1. (National Examination Questions in 1990) Let the center of the ellipse be the origin of the sciatic, the long axis on the x-axis, the eccentricity is, the longest distance from the known point P to the ellipse is, find the equation of the ellipse, and find the ellipse to the point P’s distance equals the coordinates of the point. Solution: Figure (1), set the ellipse square...