Integer and fractional part : propfrac

### 2.28.8 Integer and fractional part : `propfrac`

`propfrac` takes as argument a rational fraction.
`propfrac` rewrites this rational fraction as the sum of it’s integer part and proper fractional part.
`propfrac(A(x)/B(x))` writes the fraction A(x)/B(x) (after reduction), as :

Q(x)+ |
R(x)
B(x)
| where R(x)=0 or 0≤ degree(R(x))< degree(B(x))

Input :

`propfrac((5*x+3)*(x-1)/(x+2))`

Output :

`5*x-12+21/(x+2)`