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This is documentation for Caché & Ensemble. See the InterSystems IRIS version of this content.

For information on migrating to InterSystems IRIS, see Why Migrate to InterSystems IRIS?


A scalar numeric function that returns the arc-tangent, in radians, of the tangent of an angle.


{fn ATAN(float-expression)}


Argument Description
float-expression An expression of type float. This is the tangent of the angle.


ATAN takes any numeric value and returns the inverse (arc) of the tangent of an angle as a floating point number. ATAN returns NULL if passed a NULL value. ATAN treats nonnumeric strings, including the empty string (''), as the numeric value 0.

ATAN returns a value of data type FLOAT with a precision of 36 and a scale of 18.

ATAN can only be used as an ODBC scalar function (with the curly brace syntax).

You can use the DEGREES function to convert radians to degrees. You can use the RADIANS function to convert degrees to radians.


The following example shows the effect of ATAN:

SELECT {fn ATAN(0.52)} AS ArcTangent 

returns 0.47951929199...

See Also