3.5.2.5.13 Bessel_k_nu

Definition:

k\_nu =bessel\_k\_nu(x,nu) evaluates an approximation to the modified Bessel function of the second kind K_{\upsilon /4}(x), where the order =-3, -2, -1, 1, 2 or 3 and x is real and positive. For negative orders the formula

K_{-\upsilon /4}(x)=K_{\upsilon /4}(x)

is used. For more information please review the s18efc function in the NAG document.

Parameters:

x (input, double)
The argument x of the function.
Constraints:
x>0.0.
nu (input, int)
The argument \nu of the function.
Constraints:
1\leq abs(nu)\leq 3
k\_nu (output, double)
Approximation of the modified Bessel function of the second kind.