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Definition Bx_R (intruder evader : State) : R :=
  (-2 * (yt evader * sind (heading intruder) * intruderSpeed) +
   2 * (yt intruder * sind (heading intruder) * intruderSpeed) -
   2 * (cosd (heading intruder) * xt evader * intruderSpeed) +
   2 * (cosd (heading intruder) * xt intruder * intruderSpeed) +
   2 * (xt evader * evaderSpeed) - 2 * (xt intruder * evaderSpeed))%R.Definition C_R (intruder evader : State) : R :=
  (Rsqr (yt intruder - yt evader) + Rsqr (xt intruder - xt evader))%R.

Lemma Rsqr_R : forall (intruder evader : State) (t : R), Rsqr (RR intruder evader t) = (Ax2_R intruder * Rsqr t + Bx_R intruder evader * t + C_R intruder evader)%R.