Simplify : simp2

### 2.28.6 Simplify : `simp2`

`simp2` takes as argument two polynomials (or two integers see 2.8.6). These two polynomials are seen as the numerator and denominator of a rational fraction.
`simp2` returns a list of two polynomials seen as the numerator and denominator of an irreducible representant of this rational fraction.
Input :

`simp2(x```^```3-1,x```^```2-1)`

Output :

`[x```^```2+x+1,x+1]`