Write a Matlab function my Sin $3x$ that takes as input $x$ and the number $N$ to estimate $sin(3x)$ using

$sin(3x)$~~${\displaystyle \underset{n=0}{\overset{N}{}}}(-1{)}^n\frac{(3x{)}^{2n+1}}{(2n+1)!}$

and returns as outputs the estimate for $sin(3x)$ together with the corresponding true relative error. You may use the Matlab function factorial $()$ to calculate the factorial in the formula. For the true value of $sin(3x)$ use Matlab's build$-$in function $sin(3**x).$ Do not print out any results to screen or do any plotting within the function.