proposition: Lemma cos_coeff_2_0 : cos_coeff 2 0%N = 1 :> R.
proof: Proof. by rewrite /cos_coeff /= mul1r expr0 mulr1 expr0z divff. 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