subplot(3,1,1)
hold on
axis equal
axis([0,7.0, -1,1])
plot([0,7.0],[0,0],':k')
plot([pi/3,2*pi/3,pi,4*pi/3,5*pi/3,2*pi], ...
[cos(2*pi/3),cos(2*2*pi/3),cos(2*pi),cos(2*4*pi/3),cos(2*5*pi/3),1], '^b')
fplot('cos(2*v)',[0,2*pi],'k')
for (i=1:6)
   plot([i*pi/3,i*pi/3],[0,cos(2*i*pi/3)],'--r')
end
title('Vector v_{4}')

subplot(3,1,2)
hold on
axis equal
axis([0,7.0, -1,1])
plot([0,7.0],[0,0],':k')
plot([pi/3,2*pi/3,pi,4*pi/3,5*pi/3,2*pi], ...
[sin(2*pi/3),sin(2*2*pi/3),sin(2*pi),sin(2*4*pi/3),sin(2*5*pi/3),0], '^b')
fplot('sin(2*v)',[0,2*pi],'k')
for (i=1:6)
  plot([i*pi/3,i*pi/3],[0,sin(2*i*pi/3)],'--r')
end
title('Vector v_{5}')

subplot(3,1,3)
hold on
axis equal
axis([0,7.0, -1,1])
plot([0,7.0],[0,0],':k')
plot([pi/3,2*pi/3,pi,4*pi/3,5*pi/3,2*pi], ...
[cos(3*pi/3),cos(3*2*pi/3),cos(3*pi),cos(3*4*pi/3),cos(3*5*pi/3),1], '^b')
fplot('cos(3*v)',[0,2*pi],'k')
for (i=1:6)
   plot([i*pi/3,i*pi/3],[0,cos(3*i*pi/3)],'--r')
end
title('Vector v_{6}')

