It's been a while since I've been in a math class. I'm just trying to make a simple openGL demo, and I ran into this problem. If you look at the picture, I know the values of: x, y x', y' θ Now, from those, how can I find X2' and Y2' on a cartesian coordinate system? lol, the question might seem dumb, but I've been out of touch for a long time and while I've done some searches I did not find anything specific. Any help would be greatly appreciated! Thanks!