User Guide

Cos 417
Cos
Description
Calculates the cosine of an angle that is entered in radians.
Returns
A number; the cosine of the angle.
Category
Mathematical functions
Function syntax
Cos(number)
See also
ACos, Sin, ASin, Tan, Atn, Pi
Parameters
Usage
The range of the result is -1 to 1.
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 returns a very small number (such as
6.12323399574E-017) for angles that should produce 0. To test for a 0 value, check whether the
value is less than 0.0000000000001.
Example
<h3>Cos Example</h3>
<!--- Calculate cosine if form has been submitted --->
<cfif IsDefined("FORM.cosNum")>
<!--- Make sure input is a number --->
<cfif IsNumeric(#FORM.cosNum#)>
<!--- Convert degrees to radians, call the Cos function. --->
<cfset cosValue=#Cos((Form.cosNum * PI()) / 180)#>
<!--- 0.0000000000001 is the function's precision limit.
If absolute value of returned cosine value is
less, set result to 0 --->
<cfif Abs(cosValue) LT 0.0000000000001>
<cfset cosValue=0>
</cfif>
<cfoutput>
Cos(#FORM.cosNum#) = #cosValue#<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 cosine:
<br><input type = "Text" name = "cosNum" size = "15">
Parameter Description
number Angle, in radians, for which to calculate the cosine