- scipy.special.y1(x, out=None) = <ufunc 'y1'>#
Bessel function of the second kind of order 1.
- outndarray, optional
Optional output array for the function results
- Yscalar or ndarray
Value of the Bessel function of the second kind of order 1 at x.
The domain is divided into the intervals [0, 8] and (8, infinity). In the first interval a 25 term Chebyshev expansion is used, and computing \(J_1\) (the Bessel function of the first kind) is required. In the second, the asymptotic trigonometric representation is employed using two rational functions of degree 5/5.