# 3.5.1.3.18 Bessel_k1_scaled

## Definition:

$k1\_scaled = bessel\_k1\_scaled(x)$ evaluates an approximation to $e^xK_1\left( x\right)$, where $k_1$is a modified Bessel function of the second kind. The scaling factor ex removes most of the variation in $k_1$.

## Parameters:

x (input, double)
The argument x of the function. Constraint: x> 0.0.
$k1\_scaled$ (output, double)
Approximation of $e^xK_1\left( x\right)$