.. index:: Airy functions
.. index:: Ai(x)
.. index:: Bi(x)

The Airy functions :math:`Ai(x)` and :math:`Bi(x)` are defined by the
integral representations,

.. only:: not texinfo

   .. math::

      Ai(x) & = {1\over\pi} \int_0^\infty \cos(t^3/3 + xt ) \,dt \\
      Bi(x) & = {1\over\pi} \int_0^\infty (e^{-t^3/3 + xt} + \sin(t^3/3 + xt)) \,dt

.. only:: texinfo

   | Ai(x) = (1/\pi) \int_0^\infty \cos((1/3) t^3 + xt) dt
   | Bi(x) = (1/\pi) \int_0^\infty (e^(-(1/3) t^3 + xt) + \sin((1/3) t^3 + xt)) dt

For further information see Abramowitz & Stegun, Section 10.4. The Airy
functions are defined in the header file :file:`gsl_sf_airy.h`.

Airy Functions
--------------

.. function:: double gsl_sf_airy_Ai (double x, gsl_mode_t mode)
              int gsl_sf_airy_Ai_e (double x, gsl_mode_t mode, gsl_sf_result * result)

   These routines compute the Airy function :math:`Ai(x)` with an accuracy
   specified by :data:`mode`.

.. function:: double gsl_sf_airy_Bi (double x, gsl_mode_t mode)
              int gsl_sf_airy_Bi_e (double x, gsl_mode_t mode, gsl_sf_result * result)

   These routines compute the Airy function :math:`Bi(x)` with an accuracy
   specified by :data:`mode`.

.. function:: double gsl_sf_airy_Ai_scaled (double x, gsl_mode_t mode)
              int gsl_sf_airy_Ai_scaled_e (double x, gsl_mode_t mode, gsl_sf_result * result)

   These routines compute a scaled version of the Airy function
   :math:`S_A(x) Ai(x)`.  For :math:`x > 0` the scaling factor :math:`S_A(x)` is
   :math:`\exp(+(2/3) x^{3/2})`, 
   and is 1 for :math:`x < 0`.

.. function:: double gsl_sf_airy_Bi_scaled (double x, gsl_mode_t mode)
              int gsl_sf_airy_Bi_scaled_e (double x, gsl_mode_t mode, gsl_sf_result * result)

   These routines compute a scaled version of the Airy function
   :math:`S_B(x) Bi(x)`.  For :math:`x > 0` the scaling factor :math:`S_B(x)` is
   :math:`exp(-(2/3) x^{3/2})`, and is 1 for :math:`x < 0`.


Derivatives of Airy Functions
-----------------------------

.. function:: double gsl_sf_airy_Ai_deriv (double x, gsl_mode_t mode)
              int gsl_sf_airy_Ai_deriv_e (double x, gsl_mode_t mode, gsl_sf_result * result)

   These routines compute the Airy function derivative :math:`Ai'(x)` with
   an accuracy specified by :data:`mode`.

.. function:: double gsl_sf_airy_Bi_deriv (double x, gsl_mode_t mode)
              int gsl_sf_airy_Bi_deriv_e (double x, gsl_mode_t mode, gsl_sf_result * result)

   These routines compute the Airy function derivative :math:`Bi'(x)` with
   an accuracy specified by :data:`mode`.

.. function:: double gsl_sf_airy_Ai_deriv_scaled (double x, gsl_mode_t mode)
              int gsl_sf_airy_Ai_deriv_scaled_e (double x, gsl_mode_t mode, gsl_sf_result * result)

   These routines compute the scaled Airy function derivative 
   :math:`S_A(x) Ai'(x)`.  
   For :math:`x > 0` the scaling factor :math:`S_A(x)` is
   :math:`\exp(+(2/3) x^{3/2})`, and is 1 for :math:`x < 0`.

.. function:: double gsl_sf_airy_Bi_deriv_scaled (double x, gsl_mode_t mode)
              int gsl_sf_airy_Bi_deriv_scaled_e (double x, gsl_mode_t mode, gsl_sf_result * result)

   These routines compute the scaled Airy function derivative 
   :math:`S_B(x) Bi'(x)`.
   For :math:`x > 0` the scaling factor :math:`S_B(x)` is
   :math:`exp(-(2/3) x^{3/2})`, and is 1 for :math:`x < 0`.

Zeros of Airy Functions
-----------------------

.. function:: double gsl_sf_airy_zero_Ai (unsigned int s)
              int gsl_sf_airy_zero_Ai_e (unsigned int s, gsl_sf_result * result)

   These routines compute the location of the :data:`s`-th zero of the Airy
   function :math:`Ai(x)`.

.. function:: double gsl_sf_airy_zero_Bi (unsigned int s)
              int gsl_sf_airy_zero_Bi_e (unsigned int s, gsl_sf_result * result)

   These routines compute the location of the :data:`s`-th zero of the Airy
   function :math:`Bi(x)`.

Zeros of Derivatives of Airy Functions
--------------------------------------

.. function:: double gsl_sf_airy_zero_Ai_deriv (unsigned int s)
              int gsl_sf_airy_zero_Ai_deriv_e (unsigned int s, gsl_sf_result * result)

   These routines compute the location of the :data:`s`-th zero of the Airy
   function derivative :math:`Ai'(x)`.

.. function:: double gsl_sf_airy_zero_Bi_deriv (unsigned int s)
              int gsl_sf_airy_zero_Bi_deriv_e (unsigned int s, gsl_sf_result * result)

   These routines compute the location of the :data:`s`-th zero of the Airy
   function derivative :math:`Bi'(x)`.