Use the Piecewise Linear Algorithm to approximate the solution to the boundary-value problem
− d / dx (xy') + 4y = 4x2 − 8x + 1, 0 ≤ x ≤ 1, y(0) = y(1) = 0
using x0 = 0, x1 = 0.4, x2 = 0.8, x3 = 1. Compare your results to the actual solution y(x) = x2 − x.