Atn

Returns the arctangent of a number

Syntax
	KeyPgDeclareDeclare KeyPgFunctionFunction Atn ( KeyPgByvalByVal number KeyPgAsAs KeyPgDoubleDouble ) KeyPgAsAs KeyPgDoubleDouble

Usage
	result = Atn( number )

Parameters
	number
		A number.

Return Value
	The angle, in radians, whose tangent is number, in the range 
	[-Pi/2..Pi/2].

Description
	Atn returns the arctangent of the argument number as a KeyPgDoubleDouble within the 
	range of -TutMathAnglesPi/2 to TutMathAnglesPi/2.  The arctangent is the inverse of the KeyPgTanTan 
	function. The returned angle is measured in TutMathAnglesradians (not TutMathAnglesdegrees).

	Atn can be overloaded as operator to accept user-defined types.

Example
	Print "Pi ="; Atn ( 1.0 ) * 4
	Print Atn ( 4 / 5 )

The output would be:

	Pi = 3.141592653589793
	0.6747409422235527

Differences from QB
	* None

See also
	* KeyPgTanTan
	* KeyPgAtan2Atan2
	* TutMathIntroTrigA Brief Introduction To Trigonometry

