### 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>
<cfoutput>Radians = #myDegreesVar * pi()/180#</cfoutput>
Radians = 0.00872664625997
```

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

```
<cfset myRadiansVar = .5>
<cfoutput>Degrees = #myRadiansVar * 180/pi()#</cfoutput>
Degrees = 28.6478897565
```

This question was written by Jeremy Petersen

It was last updated on January 24, 2006.