polyint

    Examples
    --------
    >>> from numpy.polynomial import polynomial as P
    >>> c = (1,2,3,4) # 1 + 2x + 3x**2 + 4x**3
    >>> P.polyder(c) # (d/dx)(c) = 2 + 6x + 12x**2
    array([  2.,   6.,  12.])
    >>> P.polyder(c,3) # (d**3/dx**3)(c) = 24
    array([24.])
    >>> P.polyder(c,scl=-1) # (d/d(-x))(c) = -2 - 6x - 12x**2
    array([ -2.,  -6., -12.])
    >>> P.polyder(c,2,-1) # (d**2/d(-x)**2)(c) = 6 + 24x
    array([  6.,  24.])

    r