a = -1; b = 1;
xmany = linspace(a,b,500);

for n = 5:5:30,
   n,
   % Gleichverteilte Stuetzstellen
   x = linspace(a,b,n);
   w = ones(size(xmany));
   for k = 1:n,
      w = w.*(xmany-x(k));
   end
   subplot(1,2,1);
   plot(xmany,w,'k-',x,zeros(size(x)),'bo');
   title('Gleichverteilt');
   makelarge


   % Geschickt verteilte Stuetzstellen
   x = cos( ( 2*(1:n)-1 ) / 2 / n * pi );
   w = ones(size(xmany));
   for k = 1:n,
      w = w.*(xmany-x(k));
   end
   subplot(1,2,2);
   plot(xmany,w,'k-',x,zeros(size(x)),'bo');
   title('Geschickt verteilt');
   makelarge
   pause
end