@acer 

Dear everybody

I would like your help to first represent the EDO system with two parameters "K" and "a" and then represent the system in

 K-a parametric plane as in the attached png file.

Best regards

plot_with_2_parameters.mw

@Scot Gould 

Thank you so much very satisfied

@Scot Gould 

Thank you very much for help.
Is it possible to represent LE, ME, NE vs "a" (horizontal axis) for t=0..10? In other words, from the 3D representation to extract only the 2D plane (LE vs "a", ME vs "a", NE vs "a"). Once again thank you very much.

@acer 

Thank you very much for help.
Is it possible to represent LE, ME, NE vs "a" (horizontal axis) for t=0..10? In other words, from the 3D representation to extract only the 2D plane (LE vs "a", ME vs "a", NE vs "a"). Once again thank you very much.