A Better ATan2

by Matt Wolffe

ATan2 is simply an arctangent function modified to return an angle in any quadrant. Most ATan2 calculators return angles from $(- π, π]$ , which, in my opinion, is not as useful as returning an angle between $[0,2 π)$ .

Most calculators are also restricted to radians, and while the conversion to another unit is not difficult, why not just provide the option to choose from a list of 16 units? Some standard, some 'obscure'!

Definition

aTan2 (x, y) = {\begin{matrix} \arctan (\frac{y}{x}) & x > 0 and y \geq 0 \\ \arctan (\frac{y}{x}) + 2 π & x > 0 and y < 0 \\ \arctan (\frac{y}{x}) + π & x < 0 \\ \frac{π}{2} & x = 0 and y > 0 \\ \frac{3 π}{2} & x = 0 and y < 0 \\ undefined & x = 0 and y = 0 \end{matrix}

Instructions

Enter x-coordinate value
Enter y-coordinate value
Select a unit from the drop-down
Click "Calculate!"
Revel in the fact you saved however long it would have taken to find the angle manually!

x-coordinate:
y-coordinate:
Select unit

Retain Previous Outputs? Retain Overwrite