a = 0.6 (slider from -5 to 5, step 0.1)
b = 1 (slider from -5 to 5, step 0.1)
c = -2 (slider from -5 to 5, step 0.1)
d = -2.1 (slider from -5 to 5, step 0.1)
f(x) = a * x^(3.0) + b * x^(2.0) + c * x + d
A = Point(f)
e = Tangent(x(A), f(x))
m = Slope(e)
g: f'(x(A))
texte2: "Image de a par f : f(a) = " + (f(x(A)))
texte1: "Nombre dérivé en a : f'(a) = " + g
texte4: "Coordonnées du point A : ( " + (x(A)) + " ; " + (y(A)) + " )"
texte3: "Pente de la tangente en a : m = " + m