@Carl Love  perfect !Thanks

@acer  Sorry !  i want to animate the final graphic with quadric surface and his principal directions. Thanks !

 QuadricAnim.mw

@vv  Just last question, how to animate my graphics ? Thanks a lot ! QuadricAnim.mw

@vv Great ! Thanks

@vv And how to add principal planes in the final graphic ? Thanks for your help
 

Download PrincipalPlanes.mw

 PrincipalPlanes.mwPrincipalPlanes.mw

@Carl Love thanks ! 

@vv   Thanks for your code, but i have problem with the "fnew" variable 

@Kitonum 

Hi,

I am trying to add an animation of the derivated function, but I have a margin problem in my display intervals 

Ideas to solve this problem?

Thanks

Question2anim.mw

@acer  it s exactly my objective !

Thanks

@acer 

How to do transpose your  idea for G0 variable .. to  insert ' f(x)=, g(x)=, h(x)=, i(x)= ' without taking into account the random order of  function expressions ?

Thanks

TESTQCMal.mw

@tomleslie  Thanks

@mmcdara Thanks for your suggestion, but my problem is different : How to insert 3 simultaneous colors ( blue, green, yellow) in "Filled" command  like P1,P2,P3 ?

@tomleslie  Thanks for your suggestion, but my problem is different : How to insert 3 simultaneous colors ( blue, green, yellow) in "Filled" command  like P1,P2,P3 ?

@tomleslie  .. to "principal" values (which by definition will be in the range  -180..180) ?

@tomleslie