x

a = 0.5 (slider from -5 to 5, step 0.1)
A = Point(yAxis)
f(x) = a * x^(2)
B = Point(xAxis)
a_2 = Integral(f, 0, x(B))
d = Segment((0, 0), A)
c = Segment((0, 0), B)
n = 5 (slider from 1 to 10, step 1)
b = LowerSum(f, 0, x(B), n)
e = OrthogonalLine(B, xAxis)
C = Intersect(f, e)
g = Segment(B, C)
Liste1 = Sequence((i, f(i)), i, 0, x(B), x(B) / n)
Text1: "A_{Untersumme} = " + b + " E^2"