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).

If , 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, ε = 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

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