y=x^2-2x+3

y=k

y=x^2-2x+3とy=kとの交点の個数が，\
kの値によってどのように変わるかを観察しよう．

f(x) = (x - 1)^(2) + 2
k = 2 (slider from -2 to 5, step 0.1)
g(x) = k
A_1, A_2 = Intersect(g, f)
A1 = 0
A2 = 0
list: {A1, A2}
b = If(k > 2, 2, If[k < 2, 0, 1])
text1: "解の個数は" + b + "個"