### 2.30.2 Rational function given by roots and poles : `fcoeff`

`fcoeff` has as argument a vector
whose components are the roots and poles of a rational function
*F*[*x*], each one followed by it’s multiplicity.

`fcoeff` returns the rational function *F*(*x*).

Input :

`fcoeff([1,2,0,3,2,-1]) `

Output :

`(x-1)``^`

`2*x``^`

`3/(x-2)`