Plotting Discrete Time Functions

I need to plot 5 cos(π n /6 - π/2) as a discrete tim signal. But I am not getting the proper result.

n = [-5:0.001:5];
y = 5*cos(pi*(n/2)-(pi/2)); 
stem(n,y);

What am I missing from this code to get the discrete time signals?

Answer 1

[Austin Holmes]

The original poster asked for the discrete time signal not the continuous time signal. A discrete time signal just means sampling your continuous signal at discrete time intervals.

The simplest way this can be done is by increasing your step in n.

n = [-5:0.25:5];
y = 5*cos(pi*(n/2)-(pi/2)); 
stem(n,y);

The proper way to do this would be determining a sampling rate and implementing it in your code.

Answer 2

[Freedom TSOKPO]

I've just began with Matlab and I don't even know the function stem.

But I think this code can do it

clear all; clc;

n = -5:0.001:5;

y = 5*cos((n-1)*pi/2); %5*cos(pi*(n/2)-(pi/2));

figure

% axis([-6 6 -4 4]);

plot(n,y);