In this exercise you are to perform spectral analysis on the audio signal

"piano$\_$single$\_$note.wav".

a$)$ Write a MATLAB program according to the instructions below:

Read "piano$\_$single$\_$note.wav" into a vector $x.$

Use the built$-$in function FFT to compute the frequency spectrum of $x,$

and save the result in $x.$

Create a vector freq $($in $Hz)$ that represents the actual frequencies

corresponding to the indices of $x.$

Explain the algorithm by adding comments to the program code.