### How do I perform trigonometric calculations?

ColdFusion provides functions for all of the common trigonometric calculations.

The pi() function returns the mathematical constant Pi, accurate up to 15 digits:

``````<cfset testVar = pi()>
<cfoutput>#testVar#</cfoutput>
3.14159265359
``````

The sin() function takes an angle (in radians), and returns the sine of the angle (in radians):

``````<cfset testVar = sin(100)>
<cfoutput>#testVar#</cfoutput>
-0.50636564111
``````

The cos() function takes an angle (in radians), and returns the cosine of the angle (in radians):

``````<cfset testVar = cos(100)>
<cfoutput>#testVar#</cfoutput>
0.862318872288
``````

The tan() function takes an angle (in radians), and returns the tangent of the angle (in radians):

``````<cfset testVar = tan(100)>
<cfoutput>#testVar#</cfoutput
-0.587213915157
``````

The asin() function takes a number between -1 and 1, and then returns the arcsine of that number.

``````<cfset testVar = asin(1)>
<cfoutput>#testVar#</cfoutput>
1.57079632679
``````

The acos() function takes a number between -1 and 1, and then returns the arccosine of that number.

``````<cfset testVar = acos(1)>
<cfoutput>#testVar#</cfoutput>
0
``````

The atn() function takes a number, and then returns the arctangent of that number.

``````<cfset testVar = atn(1)>
<cfoutput>#testVar#</cfoutput>
0.785398163397
``````

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

``````<cfset myDegreesVar = .5>
``````

``````<cfset myRadiansVar = .5>