f(x) = x^(2) / 2 - 3 * x + 5 / 2
α = 0 (slider from -5 to 5, step 0.5)
β = 0 (slider from -5 to 5, step 0.5)
a = 1 (slider from 0 to 2, step 0.1)
g(x) = a * (x - α)^(2) + β
texte1: "g(x)=" + g + ""
texte2: "f(x)=" + f + ""
h(x) = x^(2)