Section Cosinus2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
Global Instance lcos_morphism :
Proper (EqL ==> EqL ==> eq ==> iff) Lcos.
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Lemma lcos3_uniqueness: forall l l1 l2 a b c, Lcos3 l1 l a b c -> Lcos3 l2 l a b c -> EqL l1 l2.