User Guide

Tan 717
Tan
Description
Calculates the tangent of an angle that is entered in radians.
Returns
A number; the tangent of an angle.
Category
Mathematical functions
Function syntax
Tan(number)
See also
Atn, Cos, ACos,
Sin, ASin, Pi
Parameters
Usage
To convert degrees to radians, multiply degrees by π/180. To convert radians to degrees, multiply
radians by 180/π.
Note: Because the function uses floating point arithmetic, it can return a very small number (such as
6.12323399574E-017) for angles that should produce 0 and can return a very 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:
Parameter Description
number Angle, in radians, for which to calculate the tangent.