how can i plot this discrete function in MATLAB

Hi,

I am beginner and i dont know how can i plot a discrete function with coefficient in MATLAB. even odd.

For example this one. How can i type the code and plot it? It will be stem func that is i know.

Answer 1

[Voss]

First you have to define what values of n to calculate C_n for. I will use 0 to 10:

n = 0:10;

Now you can calculate C_n. First initialize C_n to be a vector the same size as n with all zeros:

C_n = zeros(size(n));

Then calculate the value of C_n where n is odd (the value of C_n where n is even is already 0 because that's how C_n was initialized, so we don't need to do anything else for that):

idx = mod(n,2) == 1; % logical index with value 'true' where n is odd and 'false' where n is even
C_n(idx) = 8/pi^2./n(idx).^2; % calculating and storing 8/pi^2/n^2 where idx is 'true', i.e., n is odd

Finally create the stem plot:

figure();
stem(n,C_n);

[Batuhan Samet Demirci]

Thanks a lot....

Okay i got it, i want to ask one question more,

For values of n, if i want to make it for all values -infinity to + infinity,

or

for the value that i give matlab, i mean i want to enter a value and i want matlab to understand if the value is odd or even and calculate and plot it.

[Voss]

Infinitely long vectors are not possible in MATLAB, as far as I know.

If you use a scalar n then the stem plot will have one point, but you can do that, sure. In any case, just redefine n to be what you want (instead of 0:100) in the first line of code in my answer. The rest of the code stays the same and will calculate and stem plot C_n vs n for the n you specify.