Coterminal Angles: Negatives in Radians Explained

[Tyrion101]

I've got my final test in trig coming up, and the one thing that I simply cannot get a handle on are, coterminal angles, specifically ones where you find coterminal angles for a negative angle, in my class they are mostly done in radians. I understand how to get all the angles of a positive radian, but not the negative. I think I am over thinking something here, it may just be that I don't exactly understand negative angles beyond the fact that you start the other way around. I hope this makes sense.

 

[symbolipoint]

The rotated rays point in the same direction.

negative half pi is cotermianl with three halves pi.