f(x) = x²
D = Point(xAxis)
b = Ray(D, D + (1, 0))
E = Point(b)
Fläche = Integral(f, x(D), x(E))
C: (x(E), Fläche)
a = Segment(C, (x(E), 0))
T1: "F = " + Fläche
T2: "a = " + (x(D))
T3: "b = " + (x(E))