clear all;
close all;
writerObj = VideoWriter('Vid_ellipse2.avi'); % Name it.
writerObj.FrameRate = 10; % How many frames per second.
open(writerObj);

N= 250;
dt = 2*pi/N;
subplot(2,4,2:3)
t=0:dt:2*pi;
x= cos(t-pi/4);
y= sin(t);
plot(x,y,'k','linewidth',3);
axis equal
xlim([-1.5,1.5]);
ylim([-1.5,1.5]);

subplot(2,2,3);

plot(0,0);
xlim([0,2*pi]);
ylim([-1,1]);
axis on;
title('$\cos (x-\pi/4)$','Interpreter','latex','fontsize',16);
subplot(2,2,4);

plot(0,0);
xlim([0,2*pi]);
ylim([-1,1]);
axis on;
title('$\sin x$','Interpreter','latex','fontsize',16);
mat1= linspace(-1.5,1.5,N);
for i=1:length(t)
    subplot(2,4,2:3);
    if i >1
        plot(x(i-1),y(i-1),'wo','MarkerSize',9);
        plot(x,y,'k','linewidth',3);
        plot(x(i-1)+0*mat1,mat1,'w','linewidth',2);
        plot(mat1, y(i-1)+0*mat1,'w','linewidth',2);
    end
    hold on
    plot(x(i),y(i),'go','MarkerSize',9);
    plot(x(i)+0*mat1,mat1,'b--','linewidth',2);
    plot(mat1, y(i)+0*mat1,'r--','linewidth',2);
    subplot(2,2,3);
    hold on
    plot(t(i),x(i),'b.','MarkerSize',3);
    subplot(2,2,4);
    hold on
    plot(t(i),y(i),'r.','MarkerSize',3);
    shg
    frame = getframe(gcf); % 'gcf' can handle if you zoom in to take a movie.
    writeVideo(writerObj, frame);
end;

close(writerObj);