BID

BID

This function evaluates the derivative of the Airy function of the second kind.

Function Return Value

BID — Function value. (Output)

Required Arguments

X — Argument for which the Airy function value is desired. (Input)

FORTRAN 90 Interface

Generic: BID (X)

Specific: The specific interface names are S_BID and D_BID.

FORTRAN 77 Interface

Single: BID (X)

Double: The double precision name is DBID.

Description

The function Biʹ(x) is defined to be the derivative of the Airy function of the second kind, Bi(x) (see BI).

, then the answer will have no precision. If

, the answer will be less accurate than half precision. In addition, x should not be so large that

overflows. If overflows are a problem, consider using BIDE instead. Here, ɛ = AMACH(4) is the machine precision.

Example

In this example, Biʹ (–4.9) is computed and printed.

USE BID_INT

USE UMACH_INT

IMPLICIT NONE

! Declare variables

INTEGER NOUT

REAL VALUE, X

! Compute

X = -4.9

VALUE = BID(X)

! Print the results

CALL UMACH (2, NOUT)

WRITE (NOUT,99999) X, VALUE

99999 FORMAT (' BID(', F6.3, ') = ', F6.3)

END

Output

BID(-4.900) = 0.827