atan using x/y instead of y/x

[asalga]

In chapter 3, oscillation, why is atan being passed in x/y, shouldn't it be y/x?

V1 ⇒ angle = atan(-4/3) = atan(-1.25) = -0.9272952 radians = -53 degrees
V2 ⇒ angle = atan(4/-3) = atan(-1.25) = -0.9272952 radians = -53 degrees

[shiffman]

thank you, indeed this looks like a mistake (also nature-of-code/The-Nature-of-Code-archive#199). Will check and fix when I do another round of updates!

[shiffman]

This is now how it looks, I believe this is right. Let me know if not: