# 3.5.1.3.8 Bessel_i0_scaled

## Definition:

$i0\_scaled = bessel\_i0\_scaled(x)$ evaluates an approximation to $e^{-|x|}I_0(x)$, where IO is a modified Bessel function of the first kind. The scaling factor $e^{-|x|}$ removes most of the variation in $I_0(x)$.

For more information please review the s8cec function in the NAG document.

## Parameters:

x (input, double)
The argument x of the function.
i0_scaled (output, double)
Approximation of $e^{-|x|}I_0(x)$.