К вопросу о геодезической. Записываем:
Код:
a:=1;
b:=1;
c:=1;
with(DifferentialGeometry):with(Tensor):with(Tools):
x:=proc(u,v) a*cosh(u)*cos(v); end proc:
y:=proc(u,v) a*cosh(u)*sin(v); end proc:
z:=proc(u,v) c*sinh(u); end proc:
E:=proc(u,v) simplify(diff(x(u,v),u)^2+diff(y(u,v),u)^2+diff(z(u,v),u)^2); end proc:
F:=proc(u,v) simplify(diff(x(u,v),u)*diff(x(u,v),v)+diff(y(u,v),u)*diff(y(u,v),v)+diff(z(u,v),u)*diff(z(u,v),v)); end proc:
G:=proc(u,v) simplify(diff(x(u,v),v)^2+diff(y(u,v),v)^2+diff(z(u,v),v)^2); end proc:
E(u,v);F(u,v);G(u,v);
DGsetup([u,v],M):
g1:=evalDG(E(u,v)*`&t`(du,du)+2*F(u,v)*`&t`(du,dv)+G(u,v)*`&t`(dv,dv));
R := RicciScalar(g1);
C2 := Christoffel(g1, "SecondKind"):
UV := [U(t),V(t)]:
DE := Tools:-DGinfo(GeodesicEquations(UV, C2, t),"CoefficientSet"):
q1 := op(1, op(1, DE));
q2 := op(1, op(2, DE));
#s:=dsolve([d1=0,d2=0,U(0)=-3,(D(U))(0)=0,V(0)=0,(D(V))(0)=0]);
q1=0;
q2=0;
Выхлоп Маплы:


Может Bliss поможет последнюю систему уравнений решить?
А то у меня комп не очень. А кривизна отрицательна и "растет".