@Carl Love 

I would like to know how to build a teapot from these curves "Bezier" is my question (knowing that it remains to determine the other parts of the said teapot ..).

@tomleslie 

In the 3rd term, you should put r ^ 2, especially since you did not understand my question correctly, the curve that you had, I had it too, but, I would like from this result to lead to a teapot.

@Carl Love 

What is problematic here is the square root value of Pi, which we want to have as a non-truncated value ...
This is the Maple command we are looking for, which keeps all the components of each value.
Thank you.

@Kitonum 

Ok, thanks for the idea, except that in this case, it does not really work, thank you in any case.

We must have a finite numerical value, not truncated, at the end and with a single command.

@acer 

I found this, but it is not a single command by cons:

             >  convert((evalf(1/2)!), rational, exact);
                                                                                                             1772453851
                                                                                                           -------------------
                                                                                                             2000000000
 

@acer

Thank you very much, but only one command of the form: command (factorial (1/2)) = n 

Ce n'est nullement, un TD ni TP, c'est juste des reflexions et des questionnements, qu'il m'arrive des fois de me les poser et commencer à y reflechir et que je partage et demande des avis ou suggestions ...

En tout cas, merci bcp pour le partage et la leçon de moral, et je souhaiterai ne plus avoir de réponse de ta part...!!? 

Et voila plus simple:

  > baby := proc (k, x0)

     x1 = (1/2)*x0+(1/2)*k/x0

     end proc;
               

  >  bab(7, 3);      

@Kitonum 

Thank you very much, it's appreciated..