α

α = 90°

A = (1, 0.5)
B = (2.5, 1)
g = Line(A, B)
C9 = NaN
B1: A + (1, 0)
f = OrthogonalLine(B1, xAxis)
B2 = Intersect(g, f)
u1 = Vector(A, B1)
v1 = Vector(B1, B2)
Text1: "" + (x(u1)) + ""
Text2: "" + (y(v1)) + ""
gL: -2
m1 = Slope(g)
α = If(y(B) ≥ y(A), Angle[B1, A, B2], Angle[B2, A, B1])
δ = Angle(B2, A, B1)
a: tan(δ)
m2: tan(α)
Text5: "m = " + (LaTeX[m1]) + ""
Text6: "tan(α) = " + (LaTeX[m2]) + ""
B3: (x(A), y(B2))
β = If(y(B) ≥ y(A), Angle[B2, A, B3], Angle[B3, A, B2])
β' = If(y(B) ≥ y(A), β, (-β))
α' = If(y(B) ≥ y(A), α, (-α))
Text4: "α = " + (LaTeX[α']) + ""
Text8: "β = " + (LaTeX[β']) + ""
Text3: "\frac{1}{tan(β)} = " + (LaTeX[m1]) + ""
h = Segment(B2, B3)
i = Segment(A, B3)