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ACos

Last update:
May 18, 2026

Description

Arccosine function. The arccosine is the angle whose cosine is number.

Returns

The arccosine, in radians, of a number.

Category

Function syntax

ACos(number)

See also

Cos Sin ASin Tan Atn Pi

Parameters

ParameterDescription
number
Cosine of an angle. The value must be between -1.0 and 1.0, inclusive.

Usage

The range of the result is 0 to p. To convert degrees to radians, multiply degrees by p/180. To convert radians to degrees, multiply radians by 180/p.

Example

<cfscript>
   number=0.5;
   writeOutput(acos(0.5));  // Returns 1.04719755
</cfscript>

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