fact: Definition Csqrt:=fun (z:C) => let (u,v):=z in let a:=(sqrt(((Cmod z)+u)/2))%R in let b:=(if (Rneg_or_not z) then v/2/a else sqrt(-u))%R in (a,b)%C : C.
imports: Reals Coq.Reals.Rtrigo_def Coquelicot.Coquelicot Coquelicot.ElemFct Lra