proposition: Lemma sin2 : forall x:R, Rsqr (sin x) = 1 - Rsqr (cos x).
proof: Proof. intro x; generalize (cos2 x); intro H1; rewrite H1. unfold Rminus in |- *; rewrite Ropp_plus_distr; rewrite <- Rplus_assoc; rewrite Rplus_opp_r; rewrite Rplus_0_l; symmetry in |- *; apply Ropp_involutive. Qed.
imports: Rbase Rfunctions SeqSeries Rtrigo_fun Rtrigo_def Rtrigo_alt Cos_rel Cos_plus ZArith_base Zcomplements Lia Lra Ranalysis1 Rsqrt_def PSeries_reg