function inverse_anim

     nn = 1000;
     m  = 7;

     x = [-1:1.0/nn:1];
     
     f = @(y)sin(pi*y)./y;
     a = quadl(f,0,1);
     
     S = a * sin(pi*x);
     
     for i=1:m

        for j=2^(i-1)+1:2^i
           f = @(y)sin(j*pi*y)./y;
           a = quadl(f,0,1);
           S = S + a * sin(j*pi*x);
        end
        
        N = 2^i

        h=plot(x(1:995*nn/1000),1./x(1:995*nn/1000),'k-');
        set(h,'LineWidth',2);
        hold on;
        h=plot(x(1005*nn/1000+1:2*nn+1),1./x(1005*nn/1000+1:2*nn+1),'k-');
        set(h,'LineWidth',2);
        set(gca,'LineWidth',2);
        set(gca,'FontSize',18);
        h=plot(x,S,'b-');
        set(h,'LineWidth',2);
        hold off;

        pause;
     end
