ColdFusion 9.0 Resources

Tan

Description

Calculates the tangent of an angle that is entered in radians.

Returns

A number; the tangent of an angle.

Function syntax

Tan(number)

Parameters

Parameter	Description
`number`	Angle, in radians, for which to calculate the tangent.

Usage

To convert degrees to radians, multiply degrees by p/180. To convert radians to degrees, multiply radians by 180/p.

Note: Because the function uses floating point arithmetic, it can return a small number (such as 6.12323399574E-017) for angles that must produce 0 and can return a large number (such as 1.63312393532E+016) for infinity or not a number. To test for a 0 value, check whether the value is less than 0.0000000000001. To test for an infinite value, check whether the value is more than 1E15.

Example

<h3>Tan Example</h3> 
<!--- Calculate tangent if form has been submitted ---> 
<cfif IsDefined("FORM.tanNum")> 
<!--- Make sure input is a number ---> 
    <cfif IsNumeric(#FORM.tanNum#)> 
<!--- Convert degrees to radians, call the Tan function. ---> 
<cfset tanValue=#Tan((Form.tanNum * PI()) / 180)#> 
<!--- 0.0000000000001 is the function's precision limit. 
    If absolute value of returned value is  
    less, set result to 0 ---> 
<cfif Abs(tanValue) LT 0.0000000000001> 
    <cfset tanValue=0> 
</cfif> 
<cfoutput> 
        Tan(#FORM.tanNum#) = #tanValue#<br><br> 
</cfoutput> 
    <cfelse> 
<!--- If input is not a number, show an error message ---> 
        <h4>You must enter a numeric angle in degrees.</h4> 
    </cfif> 
</cfif> 
<form action = "#CGI.script_name#" method="post"> 
Enter an angle in degrees to get its tangent: 
<br><input type = "Text" name = "tanNum" size = "15"> 
<br><br> 
<input type = "Submit" name = "">&nbsp;&nbsp; 
<input type = "RESET" 
</form>

Tan