@acer  It s exactly my request . Thank you

@Rouben Rostamian  Thank you very much for this interesting animation. Is there a way to display the traces of the moving line during the animation? Thanks

@Kitonum Thanks for the idea. Additionally , Can we put the generatrixs in the background or animate the surface starting from the generatrixs? Thanks

@Rouben Rostamian  Thank you very much, it's a great  work. It will allow me to illustrate this geometric concept to my students.

@Thomas Richard  Thank you for the suggestion. I do use this command for my rotations. But, my goal is to use MathApp for rotations around y: The student traces any graph, and sees the volume that is generated around Y

@Axel Vogt 

The problem is always the same. The graph shows discontinuities in -1 and 1. Thanks

@acer thanks

@Carl Love  @acer 26489    Thank you for your insights. Last question : How to combine your two codes to have a single table .

TesTTablCombi.mw

@Carl Love 

Hi,I come back to you for this question of the display of forbidden values in a table, ( sqrt(-1), ln(-1) for example ), and the mathematical display of functions in the first column ( sqrt (x), 1/ sqrt(x) for example)   ideas ?  Thanks

TesTTablUndefined.mw

@Carl Love I imagine an educational scenario with a blank trigonometric table (to be completed by the student) before proposing the completed table as you proposed. Is there any way to do that? Thanks

@Carl Love Thanks !

@acer Thank you for your precious help. How to do if I want to substitute 'undefined' with the logic symbol (  don't exist for example) or other symbol.

Thanks

@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