# airy_bi

## Definition:

$Bi = airy\_bi(x)$ evaluates an approximation to the Airy function Bi(x). It is based on a number of Chebyshev expansions.

For more information please review the s17ahc function in the NAG document.

## Parameters:

x (input, double)
The argument x of the function.
$Bi$(x) (output, double)
Approximation of the Airy function$B_i(x)$