title: How to rotate coordinate system?
body: <p>I am trying to find the new value of a coordinate if I rotate around the origin.</p>
  
  <p>For example, say I have the point (1,1).
  If I rotate the coordinate axis 45 degrees around the origin, the transformed coordinate would be (0,1.414)</p>
  
  <p>Is there a way to do this efficiently in cocos2d, or in objective-c ?
  Even answers explaining the math to do this would be helpful.</p>