proposition: Lemma acos_1 : acos 1 = 0.
proof: Proof. unfold acos; repeat case Rle_dec; lra. Qed.
imports: Lra Rbase PSeries_reg Rtrigo1 Rtrigo_facts Ranalysis_reg Rfunctions AltSeries Rseries SeqProp Ranalysis5 SeqSeries PartSum Lia