ATN2

Action

ATN2 is a four-quadrant arc-tangent.

While the ATN-function returns from -p/2 (-90°) to p/2 (90°), the ATN2 function returns the whole range of a circle from -p (-180°) to +p (180°). The result depends on the ratio of Y/X and the signs of X and Y.

Syntax

var = ATN2( y, x )

Remarks

Var	A floating point variable that is assigned with the ATN2 of variable y and x.
X	The float variable with the distance in x-direction.
Y	The float variable with the distance in y-direction

atn2

Quadrant	Sign Y	Sign X	ATN2
I	+	+	0 to p/2
II	+	-	p/2 to p
III	-	-	-p/2 to -p
IV	-	+	0 to –p/2

If you go with the ratio Y/X into ATN you will get same result for X greater zero (right side in coordinate system) as with ATN2. ATN2 uses X and Y and can give information of the angle of the point over 360° in the coordinates system.

All trig functions work with radians. Use deg2rad and rad2deg to convert between radians and angles.