$(8$ points$)$ The monthly payment $M$ of a loan of amount $P$ for $N$ years and an annual interest

rate $r($in $\%)$ can be calculated by the formula:

$M=P\frac{\frac{r}{1200}}{1-(1+\frac{r}{1200}{)}^{-12N}}$

$(1)$ Write a MATLAB user$-$defined function $($named amort$)$ that calculates the monthly

payment of a loan. The input arguments of the function are $P($the loan amount$),r($the

annual interest rate in percent$),$ and $N($the length of the loan in years$).$ You can assume

that all the input arguments are single$-$valued.

$(2)$ Write a MATLAB script file that

a$)$ prompts the user to enter a value for the loan amount, a value for the annual interest

rate in percent, and a value for the length of the loan in years

b$)$ calls the amort function to calculate the monthly payment

c$)$ prints the calculated monthly payment on the command window as follows:

The monthly payment is $$x.$

where $x$ is the calculated monthly payment amount with two digits after the decimal point.

For example, if the user enters $260000$ as the loan amount, $6\mathrm{.}75$ as the interest rate $($in

percent$),$ and $15$ as the length of the loan $($in years$),$ you program should output the

following to the command window:

The monthly payment is $$2300\mathrm{.}76.$

What to submit for this question: Please submit a plain text file $($named a$4$q$4.$txt$)$ that

contains the contents of both the function file and the script file.