x=0.01:0.01:2*pi;
s1=sin(x);
s2=cos(x);
Z1=s1+s2;
Z2=-s1+s2;
Z3=-s1-s2;
Z4=s1-s2;
plot(x,Z1,'r');
hold
plot(x,Z2,'g');
plot(x,Z3,'c');
plot(x,Z4,'b');
set(gca,'XTick',0:pi/4:2*pi);
set(gca,'XTickLabel',{'0','pi/4','pi/2','3pi/4','pi','5pi/4','3pi/2','7pi/4','2pi'});
text(pi/8,cos(pi/8)+sin(pi/8),'\leftarrow cos + sen',...
'HorizontalAlignment','left')
text(11*pi/8,-cos(11*pi/8)+sin(11*pi/8),'\leftarrow - cos + sen',...
'HorizontalAlignment','left')
text(7*pi/8,-cos(7*pi/8)-sin(7*pi/8),'\leftarrow - cos - sen',...
'HorizontalAlignment','left')
text(3*pi/8,cos(3*pi/8)-sin(3*pi/8),'\leftarrow cos - sen',...
'HorizontalAlignment','left')
grid on
