% plot Lagrange polynomials on [a,b]

a = -1;
b =  1;
N =  7;



% plot the interpolation points
figure(1); clf;
fs = 24; %font size
grid on;
xlabel('x', 'FontSize', fs); ylabel('y', 'FontSize', fs);
axis([-1 1 -1 1]);
hold on;

% points for visualization
Xf = linspace(a,b,100);
ColorSet = lines(N);
for i = 1:N,
    % form the Chebyshev polynomial i
    Ti = @(x) cos(i*acos(x));
    % plot it
    plot(Xf,arrayfun(Ti,Xf),'-',...
         'LineWidth',3,'Color',ColorSet(i,:));
    if(i<N), pause; end
end
hold off;