39. The following MATLAB commands create a sine-shaped signal y(t) that contains random noise:

t = 0:.05:10;

y = sin(t)-0.1+0.2*rand(1,length(t));

Write a MATLAB program that uses these commands to create a noisy sine-shaped signal. Then the program smooths the signal by using the threepoints moving-average method. In this method the value of every point i, except the first and last, is replaced by the average of the value of three adjacent points (i–1, i, and i+1). Make a plot that display the noisy and smoothed signals.