Esperanza matematica mediante discretización
Author: Fernando San Segundo

$\mbox{Intervalo en } x_i$

$\approx f(x_i)$

c_1 = 0
c_2 = 0
NumRect = 2 (slider from 2 to 300, step 1)
f(x) = 1 / (1 + x^(4))
a = -1.5 (slider from -10 to 10, step 0.5)
b = 0.8 (slider from -5 to 5, step 0.1)
AreaAprox = LowerSum(f, a, b, NumRect)
A: (a, 0)
B: (b, 0)
Integral = Integral(f, a, b)