% Lab 2
% Question 2 on periodicity

% Define the samples axis (0 to 50, including 50)
n=0:1:50;

% Define four cosines at different frequencies
x1=cos(2*pi*n/7);
x2=cos(2*pi*n/21);
x3=cos(2*pi*n/17.5);
x4=cos(2*n/7);

% Plot each of the cosines in a separate subplot
subplot(411)
stem(n,x1,'linewidth',2)
subplot(412)
stem(n,x2,'linewidth',2)
subplot(413)
stem(n,x3,'linewidth',2)
subplot(414)
stem(n,x4,'linewidth',2)
xlabel('n');