Section Cosinus2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma lcos2_eq_trans : forall l1 a b l2 c d l3 e f, Eq_Lcos2 l1 a b l2 c d -> Eq_Lcos2 l2 c d l3 e f
-> Eq_Lcos2 l1 a b l3 e f.