f

x_0

x_1

x_2

x_3

x_4

b = 10
a = -1 (slider from -5 to 5, step 0.1)
f(x) = 3 * x - (x - 2)^(3) + x^(4) / 20
g = Function(f, a, b)
e = Integral(f, a, b)
n = 4
dx: (b - a) / n
list1 = Sequence((a + dx * i, 0), i, 0, n)
c = LeftSum(f, a, b, n)