Hệ số góc: k = tanα

k\;=\;  \frac{ u_2 }{u_1 } 

M_0 = (x_0;y_0)

\left\lbrace {x=x_0+tu_1 \atop y=y_0+tu_2}

Phương trình đường thẳng Δ

 \vec{ u }\;=\;(u_1;u_2) 

A_1 = (0.9633669880884876, 3.3323380601247887)
B = (2.8082223482699926, 4.650091888825863)
u = Vector(A_1, B)
a = Line(A_1, xAxis)
b = Line(B, yAxis)
C = Intersect(a, b)
u_2 = Segment(B, C)
u_1 = Segment(C, A_1)
α_1 = Angle(C, A_1, B)
M_0 = (4.391922561879355, 1.7807103366093937)
Δ = Line(M_0, u)
A = Intersect(Δ, xAxis)
O = Intersect(yAxis, xAxis)
D = (1.387443832440904, -3.947126305477946)
E = (3, -4)
d = Segment(D, E)
e = Circle(A, d)
F = Intersect(e, Δ, 2.0)
G = Point(e)
α = Angle(G, A, F)
v = Point(Δ)