# 3.5.2.5.4 airy_bi_deriv

## Definition:

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

For more information please review the s17akc function in the NAG document.

## Parameters:

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