F_1 = (0, 0)
F_2: (2, 0)
k = 0.62 (slider from 0 to k', step 0.01)
c = Circle(F_1, 1)
A = Point(c, k)
M = Intersect(LineBisector[F_2, A], Line[F_1, A])
loc1 = Locus(M, k)
f = Segment(M, F_1)
g = Segment(M, F_2)
text1 = LaTeX("||MF_1|-|MF_2||=|" + f + "-" + g + "|=" + (abs(f - g)))
k' = 0.62 (slider from 0 to 1, step 0.01)

Tool: 简易坐标系
请选择原点，分别输入：x最小、最大值，y最小、最大值
Input: A, a, b, c, d
Output: B, C, O, u, v

$\huge\textcolor{}{x}$

$\huge\textcolor{}{y}$

$\Large\textcolor{}{O}$

A: (0, 0)
u = Vector(A + (a - 1, 0), A + (b + 1, 0))
v = Vector(A + (0, c - 1), A + (0, d + 1))
B: A + (b + 1, 0)
C: A + (0, d + 1)
O: A