CFML Reference
ColdFusion Functions

Atn

Description

Arctangent function. The arctangent is the angle whose tangent is number.

Return value

The arctangent of a number.

Category

Mathematical functions

Syntax

Atn(number) 

See also

Tan, Sin, Cos, Pi

Parameters

Parameter	Description
number	Tangent of an angle

Usage

The range of the result is -π/2 to π/2 radians. To convert degrees to radians, multiply degrees by π/180. To convert radians to degrees, multiply radians by 180/π.

Example

<h3>Atn Example</h3>
<!--- output its Atn value --->
<cfif IsDefined("FORM.AtnNum")>
  <cfif IsNumeric(FORM.AtnNum)>
    Atn(<cfoutput>#FORM.AtnNum#</cfoutput>) = 
     <cfoutput>#Atn(FORM.AtnNum)# radians = 
      #Evaluate(Atn(FORM.AtnNum * 180/PI())# 
       Degrees</cfoutput>
  <cfelse>
<!--- if it is empty, output an error message --->
    <h4>Enter a number</h4>
  </cfif>
</cfif>
<form action = "atn.cfm">
<p>Enter a number to get its arctangent in Radians and Degrees
<br><input type = "Text" name = "atnNum" size = "25">
<p><input type = "Submit" name = ""> <input type = "RESET">
</form>

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