文[1]给出了如下性质:性质1已知直线l是圆锥曲线Γ的焦点F对应的准线,过l上一点P作曲线Γ的两条切线PA,PB,过焦点F作直线l′与准线l平行,并且分别与PA,PB交于点G,H,则|GF|=|FH|.文[2]将焦点、准线的概念推广到类焦点、类准 [1] gives the following properties: Property 1 Known line l is the alignment of the focal point F of the conic curve Γ, the two tangent lines PA, PB of the curve Γ over the previous point P, and the line L of the focal point F ’Is parallel with the line l, and PA and PB, respectively, at points G, H, then | GF | = | FH |