Making $2-$D plots. Write a separate m$-$file for each part. Remember to print each plot to its separate PNG file and additionally write a text file with comments for the whole problem to explain briefly how you solved the problem.

$($a$)$ Plot each of the following functions over each specified domain. f $($x$)=2$ sin$($x$)+$ cos$($x$),$ x in $[2\backslash$pi $,2\backslash$pi $]$

g$($x$)=$ ex cos$($x$),$ x in $[0,2\backslash$pi $]$ h$($x$)=1,$ x in $[5,5]$

$($b$)$ Let

fk$($x$)=1,$ x in $[\backslash$pi $/2,\backslash$pi $/2].$ cos$2$ x$+$k$2$ sin$2$ x

Plot the function fk$($x$)$ for k $=2,3,$ and $4$ in the same graph. You will need to use hold on before you use plot and hold off after the final plot to ensure all lines show up in the axes. Add annotations to make the plot more effective.