# numpy.polysub

numpy.polysub(a1, a2)

  Difference (subtraction) of two polynomials.

  Note

  This forms part of the old polynomial API. Since version 1.4, the new polynomial API defined in `numpy.polynomial` is preferred. A summary of the differences can be found in the transition guide.

  Given two polynomials a1 and a2, returns `a1 - a2`. a1 and a2 can be either array_like sequences of the polynomials’ coefficients (including coefficients equal to zero), or `poly1d` objects.

  Parameters:
    a1, a2 array_like or poly1d

      Minuend and subtrahend polynomials, respectively.

  Returns:
    out ndarray or poly1d

      Array or `poly1d` object of the difference polynomial’s coefficients.

  See also

  `polyval`, `polydiv`, `polymul`, `polyadd`

  Examples

  \[(2 x^2 + 10 x - 2) - (3 x^2 + 10 x -4) = (-x^2 + 2)\]

      >>> np.polysub([2, 10, -2], [3, 10, -4])
      array([-1,  0,  2])