References: Cornel University, https://e.math.cornell.edu>people, Jim Belk - Differential Geometry;
AI Assistant; Personal.
(a)
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Manipulate[x[t_]:={3Cos[t],3Sin[t],0};​​tHat[t_]:=Normalize[D[x[s],s]/.s->t];​​nHat[t_]:=Normalize[{-Cos[t],-Sin[t],0}];​​zHat={0,0,1};​​​​centerB[t_]:=x[t]+zHat;​​​​e1[t_]:=zHat;​​e2[t_]:=tHat[t];​​​​e1r[t_]:=Cos[3t]e1[t]+Sin[3t]e2[t];​​e2r[t_]:=-Sin[3t]e1[t]+Cos[3t]e2[t];​​​​wheelB[t_,u_]:=centerB[t]+Cos[u]e1r[t]+Sin[u]e2r[t];​​pB[t_]:=centerB[t]-e1r[t];​​​​Show[ParametricPlot3D[pB[t1],{t1,0,t},PlotStyle->{Blue,Thick}],​​Graphics3D[{​​Black,Thick,Line[Table[x[s],{s,0,2π,0.01}]],​​Black,Thick,Line[Table[wheelB[t,u],{u,0,2π,0.01}]],​​Black,PointSize[Large],Point[pB[t]],​​Black,Thick,Line[{centerB[t]-e1r[t],centerB[t]+e1r[t]}],​​Black,Thick,Line[{centerB[t]-e2r[t],centerB[t]+e2r[t]}]​​}],​​​​Boxed->False,​​Axes->False,​​PlotRange->{{-5,5},{-5,5},{-2,2}},​​ViewPoint->{2,-2,1.5},​​ImageSize->Large],​​{t,0.00001,2π}​​]
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(b)
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​​Manipulate[x[t_]:={3Cos[t],3Sin[t],0};​​tHat[t_]:=Normalize[D[x[s],s]/.s->t];​​nHat[t_]:=Normalize[{-Cos[t],-Sin[t],0}];​​zHat={0,0,1};​​​​uHat[t_]:=Normalize[nHat[t]+zHat];​​centerB[t_]:=x[t]+uHat[t];​​​​e1[t_]:=uHat[t];​​e2[t_]:=tHat[t];​​​​e1r[t_]:=Cos[3t]e1[t]+Sin[3t]e2[t];​​e2r[t_]:=-Sin[3t]e1[t]+Cos[3t]e2[t];​​​​wheelB[t_,u_]:=centerB[t]+Cos[u]e1r[t]+Sin[u]e2r[t];​​pB[t_]:=centerB[t]-e1r[t];​​​​Show[ParametricPlot3D[pB[t1],{t1,0,t},PlotStyle->{Blue,Thick}],​​Graphics3D[{​​Black,Thick,Line[Table[x[s],{s,0,2π,0.01}]],​​Black,Thick,Line[Table[wheelB[t,u],{u,0,2π,0.01}]],​​Black,PointSize[Large],Point[pB[t]],​​Black,Thick,Line[{centerB[t]-e1r[t],centerB[t]+e1r[t]}],​​Black,Thick,Line[{centerB[t]-e2r[t],centerB[t]+e2r[t]}]​​}],​​​​Boxed->False,​​Axes->False,​​PlotRange->{{-5,5},{-5,5},{-2,2}},​​ViewPoint->{2,-2,1.5},​​ImageSize->Large],​​{t,0.00001,2π}​​]
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