clear all;
clf;
t = -10:0.01:10;
y1 = cos(pi*t);
y2 = cos(2*pi*t/3);
y = y1 + y2;
plot(t,y, "linewidth",3);
title('Combining Cosines');
xlabel('time (seconds)');
ylabel('y(t)');
axis([-10 10 -3 3]);
grid