Converting VBScript's Atn Function
Definition: Returns the arctangent of a number.
Granted, this one doesn't come up too terribly often in system administration scripts. Nevertheless, if you ever do need to calculate the arctangent of an angle you can do so using the System.Math class and the Atan method. This command assigns the arctangent of a 90 degree angle to the variable $a:
$a = [math]::atan(90)
When you run this command and then echo back the value of $a you should get the following: