## Store Vector elements in rows as txt....

I have a vector (matrix) that looks like this. I want to save it to txt text. But the Export function doesn't seem to do that.

M:=Vector[column](10, [{{a, b}, {b, c}}, {{d, e}, {e, f}},
{{d, f}, {e, f}}, {{a, h}, {h, i}}, {{a, i}, {h, i}},
{{d, e}, {d, f}}, {{a, h}, {a, i}},{{c, d}}, {{a, b}, {a, c}}, {{a, c}, {b, c}}]);
Export(M,"E:\\M.txt");

Error, (in Export) invalid input: Export expects its 1st argument, input, to be of type string when target=file, but received Vector(10, [{{a, b}, {b, c}},{{d, e}, {e, f}},{{d, f}, {e, f}},{{a, h}, {h, i}},{{a, i}, {h, i}},{{d, e}, {d, f}},{{a, h}, {a, i}},{{c, d}},{{a, b}, {a, c}},{{a, c}, {b, c}}])

I found that I can save it in xsl format.

with(ExcelTools): Export(M, "E:\\M.xls");

How to save M in txt format below?

## Problem with Solving a PDE...

Hi Everyone,

I intend to find the invariants of a 2nd-order Tensor using the representation of the rotational group as an Infinitesimal generator. However, maple does not seem to find the correct invariants $\tr \mathbf{a}$, $\tr \mathbf{a}^2$, $\tr \mathbf{a}^3$. Maple only returns an empty set. I can't seem to figure out why that is the case.

Here is my code

 >
 >
 >
 >
 >
 (1)
 >
 (2)
 >
 (3)
 >
 >
 (4)

Any input would be appreciated!

## Flexible beam does not give expected results....

Hello everyone,

I am first time using the Flexble Beam block, and I tried simple cantilever beam with mass at the free end. Deflection is not as I expected (comparing to my hand calculations). I have tried also to use Force instead of mass (with a same load quantity), but nothing changed. Is there something that I might be missing? Expected deflection of a free end is 15 mm (I have obtained 2,8 mm in Maplesim).

Thanks!

## Maple for individuals...

Hello there,

Is the price of 295 USD for unlimited use in time?

Kind regards,

Eduardo

Hello guys,
Can anyone recommend good books on advanced programming and other Maple topics? The books I have only have the basics.
Regards,
Oliveira

## Maple Output: Is it possible to format the d in “d...

Maple standard Output

 (1)

Desired output with an italic d (here formated manualy with the  in the menu bar)

 (2)

which reverts to roman layout either after re-execution of the worksheet or re-evaluation.

 (3)

Background:
I would like to achieve textbook style formatting of integrals in Maple output. I am aware that interpreting a dx in an integral as a "differential" is controversial. The way Maple displays the integration variable in italic and the d in roman makes sense and avoids confusion with interpretations that are no longer needed.
However, what I want to avoid is mixing
dx and dx in the same document.

Can Maple be set by default that the d in the dx of an integral becomes italic?

If this is not possible and because this question comes from habits in physics: Would a display option in the physics package be possible?

## How to fix "Error, || unexpected"?...

Execute the following codes in Maple input (1-D math) in the Standard interface.

(cat("A".."C"),cat("d".."f"))||'$"G".."I",$"j".."l"';

Then an error occurred. But if one copy them into 2-D math (instead of Convert To>2-D Math Input) and execute them directly, everything goes without any error messages.

It says that mixed 1-D and 2-D math inside one command is not supported and not recommended stylistically. However, I just want to understand the reason why an error is raised here.

 > restart;
 > kernelopts(version);
 (1)
 > interface(version);
 (2)
 > (cat("A".."C"),cat("d".."f"))||'$"G".."I",$"j".."l"';
 >
 (3)
 >

## Differential system of equations taking to long to...

Hello everyone,

I am having trouble with this a system of 12 differential equations with the respective 12 initial conditions. I try to usen dsolve with the "numeric" parameter but it stays "evaluating" forever. I tried a system of 10 equation and I got the correct answer, although the program stayed calculating for several minutes (more or less 5 minutes). Is the size of this system too much to handle for the program?

This is the system of differential equations (sys) and the initial conditions (ics) that I am trying to solve:

maple_primes_question.mw

What am I doing wrong? or is it that the program cannot handle such a large system? In that case, that would be dissappointing since I have to solve a similar system but with up to 22 differential equations and initial conditions so I am stuck...

Anyway, thank you very much for any guidance, and happy new year.

## Problem with power...

A:= <x1,y1,z1>:  B:= <x2,y2,z2>:  P :=<x3, y3, z3>:  H:=A+t*(B-A):  solve( (P-H)^+ . (B-A), t ):  'H'=eval(H, t=% );

Error, invalid powe, rhow to overcome this mistake ? Thank you.
Typesetting:-mambiguous( AAssign (x1commay1commaz1)colon  BAssign

(x2commay2commaz2)colon  P Assign(x3comma y3comma z3)colon  H

AssignA + tast(Buminus0A)colon  solveApplyFunction(

Typesetting:-mambiguous((Puminus0H)circ + ,

Typesetting:-merror("invalid power")) period (Buminus0A)comma t

)colon  (H)equalsevalApplyFunction(Hcomma tequals% )semi)

## How to defeat quotations during file import...

Simple question I cannot remember the solution of.

When I import "executable maple input" from a file, the content is imported as a string and therefore have quotation marks around the code if saved in a variable. It therefore wont execute.

How do you defeat quotation marks around  executable maple code with a command in order to execute the code ?

## Can we have an unevaluated matrix product in this ...

hello dear maple, in the following code (code attached at the bottom )

I'm curious to know if it's possible to show the product of two matrices  in an unevaluated form, so for instance something like this instead of this

UnEval_Mat.mw

## "select" command doesn't work as expected in Physi...

hello maple world, in the following code (code attached at the bottom) i wish to select the terms which have the term so i used the "select" command for this task

but as u can see from the results it also selects other terms which is wrong. so what is the mistake here

Physic_select.mw

## Not able to solve a differential equation system n...

Hi everyone,

I have been trying to solve a system of 8 differential equations (1st order) with 8 different initial conditions. The system in question is the following.

sys:={

diff(a[0](t), t) - diff(a[1](t), t) + diff(a[2](t), t) - diff(a[3](t), t) = 0,

diff(b[0](t), t) + diff(b[1](t), t) + diff(b[2](t), t) + diff(b[3](t), t) = 0,

diff(a[0](t), t) + diff(a[1](t), t) + diff(a[2](t), t) + diff(a[3](t), t) - diff(b[0](t), t) + diff(b[1](t), t) - diff(b[2](t), t) + diff(b[3](t), t) = 0,

diff(a[1](t), t) + 4*diff(a[2](t), t) + 9*diff(a[3](t), t) - 3*diff(b[1](t), t) + 12*diff(b[2](t), t) - 27*diff(b[3](t), t) = 0,

diff(a[0](t), t) - diff(a[1](t), t)/2 - diff(a[2](t), t)/2 - 16*a[2](t) + diff(a[3](t), t) + 48*a[3](t) = 0,

diff(a[0](t), t) + diff(a[1](t), t)/2 - diff(a[2](t), t)/2 - 16*a[2](t) - diff(a[3](t), t) - 48*a[3](t) = 0,

diff(b[0](t), t) - diff(b[1](t), t)/2 - diff(b[2](t), t)/2 - 48*b[2](t) + diff(b[3](t), t) + 144*b[3](t) = 0,

diff(b[0](t), t) - diff(b[1](t), t)/2 - diff(b[2](t), t)/2 - 48*b[2](t) + diff(b[3](t), t) + 144*b[3](t) = 0}

and the initial conditions are

ics:={a[0](0) = 1/8, a[1](0) = 1/4, a[2](0) = 1/4, a[3](0) = 1/8, b[0](0) = 23/24, b[1](0) = 1/12, b[2](0) = -1/12, b[3](0) = 1/24}

When I run

sols := dsolve(sys union ics, numeric)

I get the error message

Error, (in DEtools/convertsys) ODE system is insufficient to determine values for all dependent variables in the system

What is happening?

Thanks for the help.

## "use" command does not substitute Physics packag...

Hey guys. i recently faced a problem where i needed to substitute the "physics's overloaded product operator" , namely with normal matrice product (.), so maple can do the matrice product calculation after my non-commutative physics operator(yellow symbols in the following code) has been replaced with real matrices (for instance, this substitution:)

now in order to substitute  with . I have utilized the maple use command. but the problem is, it doesn't do the substitution when I utilized use command as follows (code file is attached at the bottom) :

so what's the mistake here?

Physic_subs.mw

## Is it possible to specify constants (initial posit...

Let's say we have a velocity vector v := c _i + d _j, where _i and _j are the i hat and j hat Cartesian basis vectors as present in the Physics[Vectors] package.

When we integrate this velocity vector relative to t, the result in maple is the position vector (c _i + d _j)t.

I guess that is correct.

My question is: is there am in-built way to specify an initial position vector for the integration? Ie, can I specify constants in the integration?

Right now I am just doing

s0 := sx _i + sy _j

s:= int(v, t) + s0

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