Section Cosinus2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
Global Instance lcos_morphism :
Proper (EqL ==> EqL ==> eq ==> iff) Lcos.

Lemma lcos_const_o : forall lp l a A B P, ~ Col A B P -> ~ Q_CongA_Null_Acute a -> Q_Cong l -> Q_Cong lp ->
Q_CongA_Acute a -> l A B -> Lcos lp l a ->
exists C, OS A B C P /\ a A B C /\ lp B C.