Unanswered Questions

This page lists MaplePrimes questions that have not yet received an answer

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

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?


What do you advice me:

  • 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?
     

Thanks in advance

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

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

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?

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:

q (z)= (diff(h1(z),z)+diff(h2(z),z)+diff(h3(z),z))/(h1(z)+h2(z)+h3(z))

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

Is possible to operate Grid Computing Toolbox together with Maple on one local multicore machine?

If yes, what is the proper instalation/configuration procedure on Windows or Linux?

Hey

 

Is it possible to draw a slope field for a second order differential equation with initial conditions?

 

Why 3D .eps figures produced by Maple 2020 are often excessively large?

So, it´s a little heavy to the viewer and to compile to PDF.

  • How could we reduce the size without losing any quality? 

helle to your all

 

as i can see there are functions to show steps of a calculation

such as ExpandSteps() and ShowSolution()

but would it not be possible to use these or some other function to show steps of the function called isolate()

it should be trivial since most online calculators are able to do this. and so does maple in the back - we just don't see the steps only the result

 

thanks regards mikkel

 

Hello,

I'm having some difficulty solving a set of equations. For example

dn/dt = Const*(phi - n)

ds/dt= Const*(phi-n)

s = d2 phi/dx2 + d2 phi/dy2

How do you solve a system like this? It is 2 equations with 2 unknowns, but it is the s variable that is evolved, i.e. ds/dt, instead of phi.

Anyone know of some code that could do this? (periodic boundary conditions)

Better yet, how do you formulate this as a regular ODE for n and phi?

 

Dear Users!

Hope everyone fine here. I have following three quires that need to be fix.

1. I want to collocate Vector IntXYZ1 and IntXYZ2 present in file Q1 in such a way that the first M1M2 + 2(M3-1)M2 + 2(M3-1)(M1-2) rows are zero and other rows are collocated at x=(i-1)/(M1-1), y=(j-1)/(M2-1), t=(k-1)/(M3-1) for i = 2,3,…,M1-1, j = 2,3,…,M2-1, k = 2,3,…,M3 as given as XX (of order 27 by 27 with first 25 rows are zero) for M1=M2=M3=3

 

2. Next, in file Q2 we have a Vector b with some entries which are actually the values of chi[1, 1, 1], chi[1, 1, 2],...,chi[2, 2, 2] in such a following way

(Vector(8, {(1) = chi[1, 1, 1], (2) = chi[1, 1, 2], (3) = chi[1, 2, 1], (4) = chi[1, 2, 2], (5) = chi[2, 1, 1], (6) = chi[2, 1, 2], (7) = chi[2, 2, 1], (8) = chi[2, 2, 2]})) = (Matrix(8, 1, {(1, 1) = 0, (2, 1) = 0, (3, 1) = 0, (4, 1) = 0, (5, 1) = 1.000000000, (6, 1) = 1.000000000, (7, 1) = 1.000000000, (8, 1) = .3678794412}))

Matrix B given in file Q2 have entires which are the linear cobiniation of chi[1, 1, 1], chi[1, 1, 2],...,chi[2, 2, 2]. I want to evaluate matrix B at the values of chi[1, 1, 1], chi[1, 1, 2],...,chi[2, 2, 2] which are obtained in vector b.

3. I want to recall a vector B in file Q3 at highlighted portion and B matrix is present in Q4. Which is the command to recall or export a matrix which contain in some other file like in file Q4.

I shall be very grateful for your support.

Q1.mwQ2.mwQ3.mwQ4.mw

 Let d an integer ">=5 " and 
                    "lambda  in ]-(1)/(2),-(1)/(d+1)[. "
Put
> gamma[s+1,d]=((s+1)[d]((d+1)lambda+s))/(2^(d+1)(lambda+s)[d+1]).;
We need to show that
> gamma[s+1,d]>=-(1)/(2^(s+1)),;
for 
> s=1,...,[(d+1)/(2)].;
                                   
 a[k] designates the pochhammer symbol.

Thanks a lot 

If you could assist; I am trying to set something like an asymptote or upper limit such that my plot below approaches asymptotically (below y =1 ) from negative infinity:

Download Plotting.mw

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