笔者在研究极坐标法证几何题时,发现如下一个几何定理及其推广。谨提供如下,请读者批评指教。引理设A_1(ρ_1,θ_1)、A_2(ρ_2,θ_2)为圆ρ=2acosθ(a>0)上任意二点,从极点P作弦A_1A_2的垂线,并过P作过A_1点的切线的垂线,垂足分 The author found a geometrical theorem and its generalization when studying the geodesic forensic geometry problem. I would like to provide the following, invite readers to criticize and advise. Lemma designation A_1 (ρ_1, θ_1), A_2 (ρ_2, θ_2) is any two points on the circle ρ=2acosθ (a>0), the perpendicular line of the string A_1A_2 from the pole P, and the tangent to the point A_1 over P. Vertical line