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# ACOS

Returns the angle, in radians, whose cosine is the given float expression; also called arccosine.

##### Syntax

ACOS ( float_expression )

##### Arguments

float_expression

Is an expression of the type float or real, with a value from -1 through 1. Values outside this range return NULL and report a domain error.

float

##### Examples

This example returns the ACOS of the given angle.

``````SET NOCOUNT OFF
DECLARE @angle float
SET @angle = -1
SELECT 'The ACOS of the angle is: ' + CONVERT(varchar, ACOS(@angle))
``````

Here is the result set:

``````---------------------------------
The ACOS of the angle is: 3.14159

(1 row(s) affected)
``````

This example sets @angle to a value outside the valid range.

``````SET NOCOUNT OFF
DECLARE @angle float
SET @angle = 1.01
SELECT 'The ACOS of the angle is: ' + CONVERT(varchar, ACOS(@angle))
``````

Here is the result set:

``````--------------------------------------------------------
NULL

(1 row(s) affected)

A domain error occurred.
``````