X XXXXXXxxx Oxxxxxxxxxx -- P2 1/L eE l VI at 0.=at U arctan y m0 22=dane -ee Ld eEl arctan2 e 0 2 1 21 21   = = vL m eE y at e 0 v v L m eE at y = = 2 0 e 0 arctan arctan v v v m y eEL  = = 2 e 0 2 tan v Ld m eE y = d  = p 12 p L d +- 1 y2 y o y x v0  