Develop a MATLAB script to plot the function

$y(x)=\frac{4}{}cosx+\frac{4}{9}cos3x$

where $$ is a variable input at the command prompt. Label the $x-$axis with time $($sec$)$ and the $y-$axis with $y(x)=(\frac{4}{})**cos(x)+(\frac{4}{9})**cos(3x).$ Include a descriptive header in the script, and verify that the help function will display the header. Choose $=1,3,10ra\frac{d}{s}$ and test the script.