clear all; close all;
n=200; n0=100;
x=linspace(-1,1,n);
dx=x(2)-x(1);
m=n-2;

A=zeros(m,m);
for j=1:m-1
    A(j,j+1)=1;
    A(j+1,j)=1;
end
for j=1:m
    A(j,j)=-2+dx*dx*n0;
end

[V,D]=eig(A);

for j=1:5
  eg1(1,j)=0;
  eg1(2:n-1,j)=V(:,end+1-j);
  eg1(n,j)=0;
  plot(x,eg1(:,j)), hold on
end