ArcTan(x,y)?

[Joe Horn]

(04-05-2017 12:07 PM)toml_12953 Wrote:  Is there a single function on the Prime to compute ArcTan(x,y)?

ARG((x,y)) = ARG(x+y*i) is like ATAN(y/x) but it respects the quadrants better than ATAN. Here's its description from the 50g AUR (same info applies to the Prime):

ARG
Type: Function
Description: Argument Function: Returns the (real) polar angle θ of a complex number (x, y).
The polar angle θ is equal to:
• atan y/x for x ≥ 0
• atan y/x + π sign y for x < 0, Radians mode
• atan y/x + 180 sign y for x < 0, Degrees mode
• atan y/x + 200 sign y for x < 0, Grads mode
A real argument x is treated as the complex argument (x,0).