fonction polynome du second degré
Author: prof

a = -0.2 (slider from -5 to 5, step 0.1)
b = 0.1 (slider from -5 to 5, step 0.1)
c = 0.9 (slider from -5 to 5, step 0.1)
f(x) = a * x^(2) + b * x + c
g(x) = -1 * 0.5 * x
A = Intersect(f, g, 2)
S = Intersect(f, yAxis, 1)