Can you, please, explain, why the angle between the computed plane and the given one is minimal?

Can you, please, explain, why the angle between the computed plane and the given one is minimal?

It works in MSWord 2007 as well.

It works in MSWord 2007 as well.

@alex_01 I'm sorry I just noticed that you replied (a month ago). If it is still of interest for you, tell me, please, what exactly is unclear.

Are you familiar with this?

If so, then the problem is in this equality?

Both can be shown with mathematical induction.

@alex_01 I'm sorry I just noticed that you replied (a month ago). If it is still of interest for you, tell me, please, what exactly is unclear.

Are you familiar with this?

If so, then the problem is in this equality?

Both can be shown with mathematical induction.

Could you, please, further clarify the problem? I don't understand what "3*t*d(t,x(t),diff(x(t),t))² = 0" means. What is d?

The other thing is that the error message tells you that there is only one independent variable, so there is no need to use pdsolve and you should use e.g. dsolve.

@ABond I am sorry I should have written this before. F[2,1] is a matrix containg 7 columns (first for the independent variable and others representing the dependent variables).

When you want the independet variable and the first dependent one (i.e. t and x[1](t)) - they are in the first two columns, so you can get them with:

F[2, 1][1 .. s, [1, 2]];

Then if you want e.g. t and x[2](t) (i.e. first and third column) you can type:

F[2, 1][1 .. s, [1, 3]];

and so on.

Edit: If you want to look at how you can extract chosen rows or columns from a Matrix (or a Vector), see ?LinearAlgebra/General/MVselect . In the example above I used the interval for the row index (which means all the rows in that interval) and the list for the column index, because I only wanted the listed columns.

@ABond I am sorry I should have written this before. F[2,1] is a matrix containg 7 columns (first for the independent variable and others representing the dependent variables).

When you want the independet variable and the first dependent one (i.e. t and x[1](t)) - they are in the first two columns, so you can get them with:

F[2, 1][1 .. s, [1, 2]];

Then if you want e.g. t and x[2](t) (i.e. first and third column) you can type:

F[2, 1][1 .. s, [1, 3]];

and so on.

Edit: If you want to look at how you can extract chosen rows or columns from a Matrix (or a Vector), see ?LinearAlgebra/General/MVselect . In the example above I used the interval for the row index (which means all the rows in that interval) and the list for the column index, because I only wanted the listed columns.

You're right. It's not only about 2D-Math. When I type

seq(<3, y, 11-4*y>, y = 0 .. 10);

it's OK, but when I type

A:=<3, y, 11-4*y>: seq(A,y=0..10);

then the sequence contains all the same (unevaluated) elements. This happens for 2D-Math as well. I do not know why.

What is not working? I just copied/pasted your command and it works fine.

How did you determine the function? What should the function satisfy?

How did you determine the function? What should the function satisfy?

For diagonally block matrix you can use ?LinearAlgebra[DiagonalMatrix] but if you join two 3x3 matrices, you want to get 5x5 matrix, right?

Could you, please, write more details of what you want?

If I understand it correctly you have data (X,Y) and you want to fit a function to them. What should the function look like? How did you get the Amplitude variable?