2011 Khronos Group
atan 3G
atan return the arc-tangent of the parameters

## Declaration

genType `atan` genType y genType x genType `atan` genType y_over_x

## Parameters

y

  Specify the numerator of the fraction whose arctangent to return.

x

  Specify the denominator of the fraction whose arctangent to return.

y_over_x

  Specify the fraction whose arctangent to return.

## Description

`atan` returns the angle whose trigonometric arctangent is y x or y_over_x, depending on which overload is invoked. In the first overload, the signs of y and x are used to determine the quadrant that the angle lies in. The values returned by `atan` in this case are in the range − . Results are undefined if x is zero.

For the second overload, `atan` returns the angle whose tangent is y_over_x. Values returned in this case are in the range − 2 2 .

## Version Support

#VARTABLECOLS#
#FUNCTABLEHEADER#
atan#newin11#

## See Also

sin, cos, tan

## Copyright

Copyright 2011 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.