>

restart;

>	with(plots);

Warning, the name changecoords has been redefined

>

n:=3;

>	x:=cos(n*t)-n*cos(t);y:=sin(n*t)-n*sin(t);

>	x1:=diff(x,t);y1:=diff(y,t);

>	x2:=diff(x1,t);y2:=diff(y1,t);

>	w:=x1*y2-x2*y1;

>	r:=(x1^2+y1^2)^(3/2)/abs(w);

>	xc:=x-(x1^2+y1^2)/w*y1;yc:=y+(x1^2+y1^2)/w*x1;

>	p1:=plot([x,y,t=0..2*Pi],scaling=constrained):

>	p2:=animate([xc+r*cos(s),yc+r*sin(s),s=0..2*Pi],t=0..2*Pi,scaling=constrained,frames=100,color=blue):

>	p3:=animate([(1-s)*xc+s*x,(1-s)*yc+s*y,s=0..1],t=0..2*Pi,scaling=constrained,frames=100,color=green):

>	p4:=plot([xc,yc,t=0..2*Pi],scaling=constrained,color=COLOR(RGB,0.2,0.3,0.5)):

>	display(p1,p2,p3,p4,axes=none,thickness=3);

>