在圆锥曲线的复习教学中,有一位同学向我咨询如下问题·题目已知F1、F2为椭圆x2/a2+y2/b2=1(ab0)的焦点,P为椭圆上一点·求证:点P处的切线PT必平分△PF1F2在P处的外角·在解答此题之后,我们还得到了一个重要的定理·证法1设F1(-c,0),F2(c,0),P(x0,y0)·图1对椭圆方程x2/a2+y2 In the review of the conic section, one of my classmates asked me the following questions. The topic is known as F1 and F2 are the focus of the ellipse x2/a2+y2/b2=1(ab0), and P is the point on the ellipse. Proof: Point P The tangent PT at the place must divide the outer corner of △PF1F2 at P. After answering this question, we also get an important theorem. Proof 1 Let F1(-c,0),F2(c,0),P( X0,y0) Figure 1 Pair of Elliptic Equations x2/a2+y2