close all
clear all 
clc

t = -10:.01:10;
x = cos(2*pi*t+pi/2);
y1 = sin(pi*t+pi/3);
y2 = sin(2*t+pi/3);
figure
subplot(2,1,1)
plot(t,x,t,y1,t,x+y1)
grid on
title('\omega_0=\pi')
legend('x(t)','y(t)','z(t)')
subplot(2,1,2)
plot(t,x,t,y2,t,x+y2)
grid on
title('\omega_0=2')

% printing figure in png format
set(gcf,'PaperUnits','inches','PaperPosition',[0 0 4 3])
print -dpng homework3.png -r100