Add x1[n] = exp(−n/4), −4 ≤ n ≤ 8 with x2[n] = cos(πn/4), 0 ≤ n ≤ 12. Plot x1[n], x2[n], and y[n].

Hello, I am having a problem with this. I couldn't identify where to start. Thank you.

Answer 1

[vidyesh]

Hi Albert,

The starting point would be to decide the period of signals/sample spacings. I am assuming 0.01.

1) define 'n' between -4 and 12 with increments of 0.01.

n = -4:0.01:12;

2) You can then use indexing to set the range of your signals while defining them. For example

% Define your signal, I have assumed x1 is 0 outside of mentioned range
x1 = zeros(1,numel(n));
% Define the function for all values of n
sig1 =  exp(-1*n/4);
% Define the range for which function is defined
range =  n>=-4 &  n<=8;
% Store the values of the signal within the defined range only
x1(range) = sig1(range);

3) Similarly you can plot 'x2' and calculate 'y' and then plot them:

The below documentation pages contain more information regarding the functions that need to be utilized.

1) plot: https://www.mathworks.com/help/matlab/ref/plot.html

2) array indexing: https://www.mathworks.com/help/matlab/learn_matlab/array-indexing.html