## Problem with differential operator...

hi.please see attached file below and help me.one problem is apply differential operator on matrix and then caclute 3D integral?

maple2.mw

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## How I can write a matrix of square size 15? ...

Hello

I try to write a matrix (15*15) by maple, but the maple programme doesn't run this.

Here I attached the worksheet.

 >
 >
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 >
 >
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 > n:=14:
 > for v from 0 to n do
 > p[v,n]:=expand(binomial(n,v)*x^(v)*(1-x)^(n-v))
 > end do:

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d1 := MatrixInverse[Q](d);

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 >
 >
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 >
 >
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 > n:=14:
 > for v from 0 to n do
 > p[v,n]:=expand(binomial(n,v)*x^(v)*(1-x)^(n-v))
 > end do:

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d1 := MatrixInverse[Q](d);

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## Groebner produces inconsistent result...

Hello,

Calculated a Grobasis basis. Used the 19 of the 29 equations to produce a Sylvester type matrix to get a univarite polynomial. The problem I am having is I can't produce a consistant matrix. I think the problem may lie in how I sort the equations. I have used this method once before and it worked to produce the result then. Run the worksheet and the run it again and most likely a different outcome occurs. I copy and pasted the polynmial list to make this worksheet. The coefficients are very long. Have annotated the worksheet to help explain.

## Possible bug in Eingenvalues...

I am using maple 13 to found Eingenvalues of an hermitian matrix :

M1:=Matrix([
> [lambda3+lambda4,0,0,0,0,0,lambda4/sqrt(2),0,0,I*lambda4/sqrt(2)],
> [0,lambda3/4,0,0,0,0,0,0,0,0],
> [0,0,lambda3/4,0,0,0,0,0,0,0],
> [0,0,0,lambda3/4,0,0,0,0,0,0],
> [0,0,0,0,lambda3/4,0,0,0,0,0],
> [0,0,0,0,0,lambda3,0,0,0,0],
> [lambda4/sqrt(2),0,0,0,0,0,lambda3/2,0,0,0],
> [0,0,0,0,0,0,0,lambda2,0,0],
> [0,0,0,0,0,0,0,0,lambda2,0],
> [-I*lambda4/sqrt(2),0,0,0,0,0,0,0,0,lambda4/2]
> ]);

>Eigenvalues(M1);

my surprise is that maple gives me 8 correct solutions an 2 complex eigenvalues which are not acceptable (we now that the eigenvalues for an hermitian matrix are all real) .

To understand the output of maple, first,  I suspect that the complex part of the roots was null but without success I haven't found how to do it zero...

is it a bug? Thanks a lot to cooperation

## Matrix of linear system...

Hello..  I want to know if there is anny command to show the matrix of linear system.  I recently entred a 64 equations and i solved it by command solve,  but i want to show the matrix of system..  So plz. Help

## Why doesn't matrix create?...

hi .why matrix a dont create?

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## Lower triangular matrix...

Hello everyone!

I want to generate an lower triangular matrix. Please see the attachment and help me. I am waiting your quick response.

Help.mw

## how to normalize a matrix to matrix form?...

aa3 := Normalize(<<aa2[1,1],aa2[2,1],aa2[3,1]>,<aa2[1,2],aa2[2,2],aa2[3,2]>,<aa2[1,3],aa2[2,3],aa2[3,3]>>, Euclidean);

the result is one column

how to normalize to a matrix form?

## How to convert matrix back to ...?...

For example, I havd matrix m:=[0 1 0 1 0 1 0], I want to convert it back to m:=[0,1,0,1,0,1,0]. Can someone help to solve? Thank you.

## 2D Matrix interpolation...

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Hello Mapleprime Community,

Would you be kind to help me with the attached Maple worksheet. My goal is to do a 2D interpolation given the value of SR (slenderness ratio) and E_G (Young's modulus / Shear modulus ratio) in the Matrix table Vert_Coeff with header as vector E_G and the other as vector SR. I’m confused as to how to do the interpolation. Please help.

Regards,

Moses

## Fitting of surface from matrix data...

Hey guys,

I want to fit experimental data and I was wondering if there is a special PolynomialFit function for a surface.

My data consist of a X,Y, Matrix of densities and I want to have a function describing the surface of the values. On matlab the following code will do so:

[x, y, z] = prepareSurfaceData(temps, concs, densities);
ft = fittype('poly33');
fitresult = fit([x, y], z, ft);

Maybe that gives you a better view of what I want.

Best regards

## Constructing Matrix from Expression...

Dear All

For following Algeraic expression

 >

How one can construct a matrix of the following form:

 >
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Where first row corresponds to and second row corresponds to  and the entries of matrix are coefficients of and

Regards

Hi, currently im using maple 15

the coding did work but it is not the same with the answer
here, i attach the coding with the answer

coding:
derivation := proc (A, n)
local i, j, k, t, s1, s2, m, D, sols, eqns, Andre;
eqns := {};
D := matrix(n, n);
Andre := matrix(n, n);
for i to n-1 do
for j from i+1 to n do
for m to n do
s1 := sum(A[i, j, k]*D[m, k], k = 1 .. n);
s2 := sum(A[k, j, m]*D[k, i]+A[i, k, m]*D[k, j], k = 1 .. n);
eqns := `union`(eqns, {s1 = s2})
end do end do end do;
sols := [solve(eqns)];
t := nops(sols);
for i to t do
for j to n do
for k to n do
Andre[k, j] := subs(sols[i], D[k, j])
end do end do;
print(Andre)
end do end proc

the maple result showing:

> AS1 := array(sparse, 1 .. 2, 1 .. 2, 1 .. 2, [(1, 1, 2) = 1]);

> derivation(AS1, 2);
[D11 0]
[D21 D22]

> AS2 := array(sparse, 1 .. 2, 1 .. 2, 1 .. 2, [(1, 1, 1) = 1, (1, 2, 2) = 1]);
> derivation(AS2, 2);
[0 D12]
[D21 D22]

the maple should showing

> derivation(AS1, 2);
[D11 0]
[D21 2D11]

> AS2 := array(sparse, 1 .. 2, 1 .. 2, 1 .. 2, [(1, 1, 1) = 1, (1, 2, 2) = 1]);
> derivation(AS2, 2);
[0 0]
[D21 D22]

## Changing matrix...

I have a column matrix with all the elements 1.

A:=Matrix(100, 1, 1):

I want to generate another matrix B exactly same as A but with one element changed and keeping all other elements to be same. Manually, I could do by following way:

A[1,1]:=1.1;
A;
B:=A;

But I have to do this with each of 100 elements of A. For instance, in step 1 I want only the first element changed into 1.1. In step 2 I want only the second element changed keeping all others to be 1, and go upto 100.

Could anyone give me an easy way to do this? I would like to appreciate your help in advance.

## Kernel connection has been lost...

Hello,

I receive this message when trying to export matrix to excel file:

> restart; with(ExcelTools); with(LinearAlgebra);

> C := Import("C:/SourceFile.xlsx", "Overview", "AK51:CB94");

> C := convert(C, Matrix);

> B := Import("C:/SourceFile.xlsx", "Overview", "G3:G46");

> B := convert(B, Matrix);

> IM := IdentityMatrix(44, 44);

> NP := 1/(C-IM).(-B);

> NP[6, 1];  //check if there is value. Yes, it works.

> Export(NP, "C:/ResultFile.xlsx", "Sheet1", "A1");

Thank you for any help.

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