> i1 := (2/( t^2 + 1 )) + 1;
> j1 := (2*t)/( t^2 + 1 );
> k1 := 0;
> r1 := [i1,j1, k1];
> with(plots);
> spacecurve(r1,t=0..5, axes=normal, color=red, numpoints=100, labels=[x,y,z]);
> r1d := simplify(diff(r1,t));
> r1dmag := ((simplify(r1d[1]^2 + r1d[2]^2))^(1/2));
> r1dmag2 := (2/( t^2 + 1 ));
> s1 := int(r1dmag2, t);
> T1 := tan(s/2);
> r1s := subs(t = T1, r1);
> spacecurve(r1s,s=0..6.24, axes=normal, color=red, numpoints=100, labels=[x,y,z]);
>