12-5

> restart;

> with(plots):with(plottools):

Warning, the name changecoords has been redefined

> x:=1;

> y:=cos(t);

> z:=sin(t);

> z1:=z;

> x1:=cos(s)*x-sin(s)*y;

> y1:=sin(s)*x+cos(s)*y;

> u:=arctan(cos(t));

> a:=plot3d([x1,y1,z1],s=0..Pi/2-2*u,t=-Pi/2..Pi/2,scaling=constrained):

> b:=rotate(a,0,0,Pi/2):

> c:=display(a,b):

> d:=rotate(c,0,0,Pi):

> p:=display(c,d):

> p;

> vrml(p,"c:/program files/maple 6/beauty/12-5.wrl",background_color=white);

>