Lemma R_T : forall (intr : Trajectory) (evad : EvaderTrajectory) (T : TimeT), h (tr evad) = V -> Rsqr (RR (measure2state intr 0) (measure2state (tr evad) 0) T) = (Rsqr (l intr evad T * cos (beta intr evad T + thetat intr 0) - V * T) + Rsqr (l intr evad T * sin (beta intr evad T + thetat intr 0)))%R.