2D 座標架
Author: 藍邦偉  老師

$ F $

$ A $

$ B $

$ D $

$ C $

$ 拋物線的內接直角三角形 $

$ \Delta ABC的頂點在拋物線上，$
$則斜邊必過定點$

q

q

$ 顯示定點 $

$ C' $

$ 顯示參考線與參考點 $

$ 顯示痕跡 $

u = Vector((x(Corner[1]), 0), (x(Corner[3]), 0))
v = Vector((0, y(Corner[1])), (0, y(Corner[3])))
O = (0, 0)
Q_2: 0.7 * Corner[1] + 0.3 * Corner[2]
Q_3: (x(Q_2), y(Corner[4]))
poly1, q_1, q_2, q_4, q_3 = Polygon(Corner[1], Q_2, Q_3, Corner[4])
a = 0.14 (slider from 0.07 to 1, step 0.01)
c: x = a * y^(2)
b: x = (-1) / (4 * a)
F: (1 / (4 * a), 0)
A = Point(c)
C = Point(c)
C': (x(C), -y(C))
e: y = y(C')
d = Segment(C, A)
f = OrthogonalLine(C, d)
B_1, B = Intersect(c, f)
g = Segment(B, A)
D = Intersect(e, g)
h = Segment(C, B)
poly2, c_1, a_1, b_1 = Polygon(A, B, C)
j = Segment(A, B)
k = true
r = false
s = false
α = Angle(B, C, A)
E: D