Faites varier la valeur du paramètre a (curseur).
     Observez la position des deux droites 
     ainsi que leurs coefficients directeurs.

O = Intersect(xAxis, yAxis)
a = 3.8 (slider from 0 to 10, step 0.1)
f(x) = 1 / 4 * (x^(2) - 1 - 2 * log(x))
M: (a, f(a))
b = OrthogonalLine(M, xAxis)
H = Intersect(b, xAxis)
d = Segment(H, M)
A = Point(yAxis)
c = Circle(O, A)
e = Segment(A, H)
K = Intersect(c, e, 2)
T = Tangent(M, f)
g = Line(O, K)