proposition: Lemma Re_div x y : 'Re (x / y) = ('Re x * 'Re y + 'Im x * 'Im y) / `|y| ^+ 2.
proof: Proof. by rewrite ReM ImV ReV !mulrA -mulrBl mulrN opprK. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)