Untitled (1)

>    restart;

>    with(plots): 

Warning, the name changecoords has been redefined

>    x1:=cos(t);x2:=-x1;y:=sin(t);z:=cos(2*t);

x1 := cos(t)

x2 := -cos(t)

y := sin(t)

z := cos(2*t)

>    x:=(1-s)*x1+s*x2;

x := (1-s)*cos(t)-s*cos(t)

>    p1:=plot3d([x,y,z],s=0..1,t=0..2*Pi,grid=[5,71]):

>    y1:=sin(t);y2:=-y1;x:=cos(t);z:=cos(2*t);

y1 := sin(t)

y2 := -sin(t)

x := cos(t)

z := cos(2*t)

>    y:=(1-s)*y1+s*y2;

y := (1-s)*sin(t)-s*sin(t)

>    p2:=plot3d([x,y,z],s=0..1,t=0..2*Pi,grid=[5,71],color=green):

>    display(p1,p2);

[Maple Plot]

>