The Taylor series of a function $f(x)$ about the point $x=a$ is defined by

$f(x)$~~$S_n(x)={\displaystyle \underset{i=0}{\overset{n}{}}}\frac{(x-a{)}^i}{i!}{f}^{(i)}(a),f^{(i)}(x)={?}^{\text{d}\text{e}\text{f}}\frac{d^{i}f}{d{x}^i}$

Write a $m-$function named $y=$symtaylor$(f,x,a,n)$ that calculates the Taylor series representation of a function symbolicly, where

$f$ is the function

$x$ is the function variable

$a$ is a point

$n$ is the degree of the Taylor expansion.

NOTE: You are not allowed to use the MATLAB build$-$in taylor function!