a = 1 (slider from -5 to 5, step 0.1)
b = 0 (slider from -5 to 5, step 0.1)
c = 0 (slider from -5 to 5, step 0.1)
f(x) = a * x^(2) + b * x + c
A: ((-b) / (2 * a), 0)
B: ((-b) / (2 * a), f((-b) / (2 * a)))
d = Segment(B, A)
texte1: "f:x\mapsto" + (LaTeX[f]) + ""
texte2: "-\frac{b}{2a}=-\frac{" + (LaTeX[b]) + "}{2\times " + (LaTeX[a]) + " }= " + (LaTeX[(-b) / (2 * a)]) + ""