スライダを動かして，
グラフとx軸の位置関係を
判別式Dの符号と比較しよう．

a = 0.7 (slider from 0.1 to 5, step 0.1)
b = 2.6 (slider from -5 to 5, step 0.1)
c = 0.9 (slider from -5 to 5, step 0.1)
f = Expand(a * x^(2) + b * x + c)
D: b^(2) - 4 * a * c
テキスト2: "D=(" + (LaTeX[b]) + ")^2-4\times (" + (LaTeX[a]) + ")\times (" + (LaTeX[c]) + ")=" + (LaTeX[D]) + ""
テキスト1: "$y= " + (LaTeX[a]) + "x^2+" + (LaTeX[b]) + "x+" + (LaTeX[c]) + " $"