過圓上一點的弦中點軌跡
Author: 詩琦

使用方式:移動動點A

圓心 = (0.76, 2.06)
c = Circle(圓心, 3)
定點 = (2.02, 3.7800000000000002)
動點A = Point(c)
a = Line(定點, 動點A)
B = Intersect(c, a, 2)
C = Midpoint(動點A, B)