1. Given the vector of interpolation nodes xi=[xi (1) . . . x1(N41), write a Matlab/Octave function compute_Lebesgue function.m that returns the Lebesgue function (4) evaluated at 1000 evenly-spaced nodes between xi(1) and xi(N+1). Such function should also return the Lebesgue constant (5) function [lambda, L]-compute Lebesgue function(xi) Input: xi: vector of interpolation nodes xi-[xi(1) xi(N+1)] Output: lambda: Lebesgue function N(x) evaluated at 1000 evenly-spaced nodes between xi (1) and L: Lebesgue constant AN