   Inverse Atan2?
  A while ago, I was helped with my problem of rotating my ship in a shooter game the way I wanted to. Right now, my class and I are working on a game that involves a stationary object shooting in any direction. The guys who are working on that cannot figure out how to make the object shoot in a given direction based on the angle the target reticle around the object has been rotated to point to. I had the idea to try to make an X and Y value based on the angle, the reverse of what I had done with taking an X and Y and making an angle to point my ship through Math.Atan2, but I can not find a method that does the inverse of Atan2. How do I reverse the process of Atan2?   
  x = cos(theta)y = sin(theta)   ;  ...oh. That worked. I feel stupid. I need to start remembering the geometry they teach me at school.   