Hi all. Is there a way to automate Parallelogram Law summations, the way I have shown in the drawing below. [see the link below]. The sun is at the origin. I start at 1, and the arms of the parallelogram law, are v and g. I compute the resultant [shown as bold black arrow], I then use this at 2, where the arms of the second summation are, r and g, and so.

http://3.bp.blogspot.com/-tFDkItTrHW...cond+Law_4.bmp