..
  Copyright 1988-2021 Free Software Foundation, Inc.
  This is part of the GCC manual.
  For copying conditions, see the GPL license file

.. _cotan:

COTAN --- Cotangent function
****************************

.. index:: COTAN

.. index:: DCOTAN

.. index:: trigonometric function, cotangent

.. index:: cotangent

.. function:: COTAN(X)

  ``COTAN(X)`` computes the cotangent of :samp:`{X}`. Equivalent to ``COS(x)``
  divided by ``SIN(x)``, or ``1 / TAN(x)``.

  :param X:
    The type shall be ``REAL`` or ``COMPLEX``.

  :return:
    The return value has same type and kind as :samp:`{X}`, and its value is in radians.

  :samp:`{Standard}:`
    GNU extension, enabled with :option:`-fdec-math`.

  :samp:`{Class}:`
    Elemental function

  :samp:`{Syntax}:`

  .. code-block:: fortran

    RESULT = COTAN(X)

  :samp:`{Example}:`

    .. code-block:: fortran

      program test_cotan
        real(8) :: x = 0.165_8
        x = cotan(x)
      end program test_cotan

  :samp:`{Specific names}:`
    =============  =============  ===========  =============
    Name           Argument       Return type  Standard
    =============  =============  ===========  =============
    ``COTAN(X)``   ``REAL(4) X``  ``REAL(4)``  GNU extension
    ``DCOTAN(X)``  ``REAL(8) X``  ``REAL(8)``  GNU extension
    =============  =============  ===========  =============

  :samp:`{See also}:`
    Converse function: 
    TAN 
    Degrees function: 
    COTAND