b = 1 (slider from 0.1 to 10, step 0.1)
a = 1 (slider from 0.1 to 10, step 0.1)
g(x) = b / x
f(x) = a * x^(2.0)
A = Intersect(f, g, (1.000000000000016, 1.000000000000032))
T_1 = Tangent(A, g)
T_2 = Tangent(A, f)
B = Intersect(f, T_1, 1.0)
C = Intersect(g, T_2, (-0.49999999999992106, -2.0000000000003157))
c = Tangent(B, f)
d = Line(B, C)

Tool: Angle Orienté de vecteurs (origine-vecteur-vecteur) (command AngleOriente)
Origine des représentants, 1er vecteur, 2ème vecteur
Input: O, u, v
Output: mes_θ, u', v', c, Flèche, E_θ

θ = Angle(u, v)
mes_θ: (sgn(sin(θ)) + If[sin(θ) ≟ 0.0, 1.0, 0.0]) * acos(cos(θ))
A = Translate(O, u)
B = Translate(O, v)
u' = Vector(O, A)
v' = Vector(O, B)
k: Min[1.0, Length[v'] / Length[u']] / 4.0
F_0 = Translate(O, Vector[k * u'])
F' = Rotate(F_0, (0.5 + 3.0 * abs(mes_θ) / (8.0 * 3.14)) * mes_θ, O)
F = Rotate(F_0, mes_θ, O)
L = Rotate(F', 14.999999999999998*°, F)
E = Rotate(F', 345.0*°, F)
c = CircumcircleSector(F_0, F', F)
Flèche, e, f, l = Polygon(F, L, E)
E_θ: mes_θ + " rad"