clear; 
Fq:=GF(41);
E:=EllipticCurve([Fq|4,-1]);
P2<X,Y,Z>:=ProjectiveSpace(Fq,2);
Eproj:=Curve(P2,[Y^2*Z-(X^3+4*X*Z^2-Z^3)]);
IsIsomorphic(E,Eproj);

