## why my question have been deleted...

Dear administration, I hope you all are good,why my question have been deleted? My question is a little similar to the one before, but there are still a lot of differences.I didn't do a backup which was bad.Once deleted, there is no chance of modification.

## Grading Package, Is there a possibility of alignin...

Hi,

Is there a possibility of aligning choices in a horizontal manner?

Thanks

QuizzTest1.mw

## something wrong with a function in a procedure...

Hello!

I have a difficulty with a function used in procedure. The procedure uses a multivariable function and if the specific choice of the function is not made the procedure seems to give proper result, but In case I make a specific choice of the function and then try use this procedure gives me incorrect result.

To be more exact I use Physics package (there is a need to calcute combinations of covariant derivates ). The calculations are performed in a curved space with a defined metric.

So here is the procedure:

SD2 := proc (psi) SumOverRepeatedIndices(g_[`~kappa`, `~lambda`]*(d_[kappa](d_[lambda](psi(X)))-Christoffel[`~sigma`, kappa, lambda]*d_[sigma](psi(X))))^2-SumOverRepeatedIndices(g_[`~kappa`, `~rho`]*(d_[kappa](d_[lambda](psi(X)))-Christoffel[`~sigma`, kappa, lambda]*d_[sigma](psi(X)))*g_[`~lambda`, `~tau`]*(d_[rho](d_[tau](psi(X)))-Christoffel[`~gamma`, rho, tau]*d_[gamma](psi(X)))) end proc;

If I turn to the procedure :

SD2(psi);

the result is  correct.

But  then I specify a psi function:

psi:=(t,r,x,y,z)->chi(r)+q*t;(here q is supposed to be a constant)

and turn to the procedure once again:

SD2(psi);

It gives me a wrong result.

I don't know what is the reason.

Thank you.

## Multiple people writing in the same document...

Hello, I'm a student in high-school, and i was wondering if it is possible to have multiple people writing in the same document at the same time. It would make groupwork a lot easier if I could do the writing like e.g.: google docs.
-Max

## SubString with special characters...

Here's another possible bug related to special characters (like ø, æ, å).

SubString considers each of the characters to be consisting of 2 different other ones.

Related to https://www.mapleprimes.com/questions/231765-Special-Characters-In-Maple-Workbook-Code.

 (1)

 (2)

 (3)

 (4)

## Disk partition and memory...

Hi,

I'm using Maple on a linux partition and for some time now I can't really use it anymore. For example, when I open a help window, I can't scroll through the content, and scrolling gets stuck if an image needs to be displayed. I think my partition is too full and does not have enough free space left. Doesn't Maple create a temporary file that is too big for the space available?  But I have another partition that is not in the same format as the linux partition but is nevertheless readable and writable. Is it possible, if the problem is a temporary file, that this file is written to this other partition to avoid this storage problem?
Or could it be due to a memory problem (RAM?) that did not occur before?

## partial differential equations, PDEs...

Hi,

I want to solve this system of PDEs. Please let me know how I can solve it.

Kindly find both my code written in Maple and the image of the problem.

Best,

PDE.mw

## Deleted questions again...

Two days ago I have answered a question about using numapprox:-infnorm for functions of several variables. The question is now deleted. Is it possible to find whether it was deleted by the author (even if she/he has used the "best answer" tag)?

## System of PDE's...

PDE:

(a+b)*(uxx+vxy)+c*laplacian(u)=0

(a+b)*(vxy+vyy)+c*laplacian(v)=0

a,b,c=const.  Initial:u=1/2*sin(2*theta),v=cos(theta)

Text book says: Solve by complex variable method

## How to manage regionalized language in Maplets:-El...

Hi,

I'm french and I'm working on an Imac.

The path for the desktop is  /Users/myname/Desktop.
If cur := "/Users/myname", one can easily verify this:

```IsDirectory(cat(cur, "/Desktop"))
true
```

In some application I'm developping, I use a  FileDialog Maplet to select a directory where to write a file.
For an unknown reason this maplet doesn't display the desktop with the name Desktop, but with it's french counterpart Bureau.

```# Observe thet the desktop (8th line above) is named "Desktop"
# Now run

maplet := Maplet(
FileDialog['FD1'](
'title' = "Output Directory",
'directory' = cur,
'fileselectionmode' = directoriesonly,
'onapprove' = Shutdown(['FD1']),
'oncancel' = Shutdown()
)
):

res := Maplets[Display](maplet):
StringTools:-StringSplit(res[], cur);

["", "/Bureau"]
```

As a result, saving a file in cur/Bureau generates an error.
Here is a more detailed worksheet:
English_French_confusion.mw

Of course I have adjusted my code in an ad hoc way by french translating  what the maplet returns, but it is just a band-aid on a larger wound. For instance "Downloads" appears as "Téléchargements", and so on, and many names potentially need to be translated.

I do not understand why FileTools seems to "work in english" while  FileDialog seems to "work in french".
I suspect this is due to the fact that my Imac, although natively "English speaking", uses a French overlay.
For instance the  Unix command pwd run in a terminal window indicates Users or Desktop, while  < command + i > executed on a given file displays Utilisateurs and Bureau.
Could it be that FileTools relies upon English, while FileDialog  relies upon the regionalized language?

• to intervene at the Apple level by changing the "user" language my Imac uses,
• to intervene at the FileDialog  level (if possible),
• or to keep translating undesired outcomes from FileDialog?

## How to find total derivative by using total deriva...

I have two functions u(x,y,t) and p(x,y,t).

I want to find the total derivative of D_x( p*u) (where * is the multiplication)

where D_x is as given in the attached file formula_of_D_x.pdf

Also, it is given in the following link but it's not clear to me. I think it somehow resembles my query, but not clear about the syntax so that I should implement it on mine.

https://www.maplesoft.com/support/help/Maple/view.aspx?path=DifferentialGeometry/JetCalculus/TotalDiff

## Maple Player / import libraries...

Any idea of how to import necessary libraries for use in Maple Player?

## why did my questions deleted...

Dear administration, I hope you all are good, why my question have been deleted? Even my important question on legends was deleted.

Two questions posted by AHSAN have just been deleted.
They were somewhat redundant with a previous one, which probably justifies their deletion.
Nevertheless, some had given AHSAN answers or replies: in this case, could the answers not be kept in some place? Perhaps in the question that the "eraser" thought was the original question?

## How do I extract the data of multiple plots into a...

Dear all,

I have 3 ODE's that I solved with the use of a for loop that cycles through different IC's. The purpose of this is so that I can compare the solutions with different IC's. I have three dependent variables (h1(z), h2(z), h3(z)), and one independent variable (z). The loop that I created looks like this:

```_Omega_r := 10^(-5); n := 10; for i from 0 to n do:     h10[i] := 1-0.16666667e-1*i;     h20[i] := 1-(.7*0.16666667e-1)*i;     h30[i]:= 3-h10[i]-h20[i];     ans := dsolve([eq2, eq3, eq4, h1(0) = h10[i], h2(0) = h20[i], h3(0) = h30[i]], {h1(z), h2(z), h3(z)}, numeric, output = listprocedure);     h1_sol[i] := rhs(ans[2]);     h2_sol[i] := rhs(ans[3]);     h3_sol[i] := rhs(ans[4]);     print(i); end do```

Here, h10[i], h20[i] and h30[i] are my initial conditions. I use h1_sol[i], h2_sol[i] and h3_sol[i] to make plots of the solutions:

I make two different types of plots - one type has only the different solutions for h1(z) with all initial conditions:

`h1plot := plot([seq(h1_sol[i](z), i = 0 .. 10)], legend = [h1(0) = h10[0], h1(0) = h10[1], h1(0) = h10[2], h1(0) = h10[3], h1(0) = h10[4], h1(0) = h10[5], h1(0) = h10[6], h1(0) = h10[7], h1(0) = h10[8], h1(0) = h10[9], h1(0) = h10[10]], title = "z versus h1(z) for different initial conditions", labels = ["z", "h1(z)"]);`

And the other uses one set of initial conditions, but all three h1(z), h2(z), h3(z):

`allplot1 := plot([seq(h1_sol[i](z), i = 2), seq(h2_sol[i](z), i = 2), seq(h3_sol[i](z), i = 2)], title = [typeset(h(z), " versus ", z, " (case 2)")], labels = [z, h(z)], legend = [typeset(h[1](z), " with ", h1__0 = h10[2]), typeset(h[2](z), " with ", h2__0 = h20[2]), typeset(h[3](z), " with ", h3__0 = h30[2])]);`

Now, all of this works wonderfully. I managed to do everything I wanted. Except that I have been struggling figuring out how to extract the data from the plots into a .dat file into different columns. With the code that I did write, if I use it on the first plot, I end up getting 2 columns, one for z and one for h1(z) (for example), but there should be 11 columns (one for z and 10 for h1(z) with different initial conditions). How would I go about to extract the data of multiple plots into one .dat (or .xls, or .csv or whatever) file? What I did:

```write := proc (plotname, filename)     local fd; fd := fopen(filename, WRITE, TEXT);     writedata(fd, convert(op([1, 1], plotname), matrix));     fclose(fd); end; write(h1plot, `zvsh1GR.dat`)```

Alternatively, if there is a way to use the solution in Maple directly without extracting first (I need to use the solutions for h1(z), h2(z), h3(z) to plot different equations that are dependent on these variables), that would be great. For example, I would like to use these three variables in an equation that uses both the derivatives of all three the variables and the variables themselves as is. For example:

And then I want to plot q(z) vs z.

I'm sorry if this is a lengthy question (or one with a simple solution) - I am still learning Maple.

My Maple file:
Solving_GR_f(R)_ne_2.maple

Maple worksheet: Solving_GR_f(R)_ne_2.mw

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