thanks for all.

@acer thanks so much

@Kitonum thanks for your help.

But do you have another way to express exactly the interval value of two variables S and a?

I need it for optimal process.

Thanks again.

Thank for all. 

My programe is correct. I only change "v" by "V" in use the Kitonum's code to have it.

I'm very happy.

Good luck!

I export data from 2 while loop as follow:

V[i] := vector[row]([h, r, delta])        { h,r are variables of loop; delta is a root}

and then I have:

> V;

[[0.01, 1, -0.31408521], [0.012, 1, -0.3772537], [0.014, 1, -0.4405360], [0.012, 1.1, -0.38068661],

[0.01, 1.1, -0.3169409], [0.01, 1.2, -0.3198507], [0.014, 1.1, -0.4445460], [0.012, 1.2, -0.3841846], [0.014, 1.2, -0.4486336]]

> V[1];

[0.01, 1, -0.31408521]

> V[2];

[0.012, 1, -0.3772537]

>V[3];

[0.014, 1, -0.4405360]

>V[4];

[0.012, 1.1, -0.38068661]

>

>

>V[8];

[0.012, 1.2, -0.3841846]

>V[9];

[0.014, 1.2, -0.4486336]

>

>

>V_matrix := <seq(V[i], i = 1 .. 9)>;

[[0.01, 1, -0.31408521]]

[                                    ]

[[0.012, 1, -0.3772537]]

[                                    ]

[[0.014, 1, -0.4405360]]

[                                    ]

[[0.012, 1.1, -0.38068661]]

[                                    ]
[                                    ]

[[0.012, 1.2, -0.3841846]]

[                                    ]

[[0.014, 1.2, -0.4486336]]

I can't plot3d with this matrix. I need a martix (nx3)

Notice to double brackets "[[    ]]' in my matrix

Thanks for your answer, but it still not run when i use the command of Kitonum.

Notice that in V[i] don't have "," between elements of it. I think this is the problem of program