proposition: Lemma acos_lepi x : -1 <= x <= 1 -> acos x <= pi.
proof: Proof. by move=> /acos_def[/andP[]]. Qed.
imports: mathcomp(all_ssreflect ssralg ssrint ssrnum matrix) mathcomp(interval rat) mathcomp(mathcomp_extra boolp classical_sets functions) reals ereal nsatz_realtype signed topology normedtype landau sequences derive realfun exp