3.5.2.5.12 Bessel_j1

Definition:

j1= bessel\_j1(x), evaluates an approximation to the Bessel function of the first kind J_1(x) .

The function is based on Chebyshev expansions.

For more information please review the s17afc function in the NAG document.

Parameters:

x (input, double)
The argument x of the function.
j1 (output, double)
The approximation of the Bessel function of the first kind.