math.atan

math.atan Function
Syntax math.atan( num : number )
Returns	number
API	math
Source	Lua (source)

Returns the arctangent (inverse tangent) of num (in radians). This is equivalent to $\arctan(x)$. To convert the output to degrees, you can use math.deg (for example: math.deg(math.atan(0.5))).

Name	arctangent
Lua function	math.atan
Usual notation	$y=\arctan(x)$
Definition	$x=\tan(y)$
Domain of x for real result	all real numbers
Range of usual principal value (radians)	$-{\frac {\pi }{2}}<y<{\frac {\pi }{2}}$

ExamplePrint the arctangent of user input
Read a line from the user, print its arctangent in radians, then in degrees.
Code	local num = math.atan(tonumber(read())) print(num) print(math.deg(num))
Output	Depends on what the user wrote. For instance, if they were to enter 0.5, the numbers printed would be 0.46364760900081 and 26.565051177078.