f(x) = If[1 ≤ x ≤ 5, 2^(sin(x))]
keskisumma = RectangleSum(f, 1, 5, 4, 0.5)
tarkka = Integral(f, 1, 5)
p = 10 (slider from 1 to 500, step 1)
alasumma = LowerSum(f, 1, 5, p)
yläsumma = UpperSum(f, 1, 5, p)