# Numerator after simplification: numer

### 5.32.2 Numerator after simplification: numer

The numer command finds the numerator of a rational function, after it has been reduced. (See also 5.7.3.)

- numer takes one argument:
  rat, a rational function.
- numer(rat) returns the numerator of the irreducible representation of rat.

#### Examples.

- Input:
  numer((x^2-1)/(x-1))
  Output:

  x+1

- Input:
  numer((x^2+2*x+1)/(x^2-1))
  Output:

  x+1