clear all

L1 = 0.2;
L2 = 0.5;

th = 0:pi/20:4*pi;
alfa = asin(L1*sin(th)/L2);

for i=1:length(th)
    
  x1 = L1*cos(th(i));
  y1 = L1*sin(th(i));
    
  x2 = L1*cos(th(i)) + L2*cos(alfa(i));
    
  plot([0 x1],[0 y1],'k-','linewidth',3)
  hold on
  plot([x1 x2],[y1 0],'r-','linewidth',2)
  plot(x2,0,'bs','markersize',10)
  hold off
  grid on
  axis([-0.3 0.8 -0.55 0.55])
  axis square
  pause(0.1)
    
end