How can I plot stream lines between two concentric spheres?

Just wanted to ask, what the issue here is:

restart;
Int(1/(1 - x*ln(x)), x);
IntegrationTools:-Change(%,u=1-x*ln(x),u);

doesn't give the proper transformation. It gives

Int(1/u,u)

Solving for x and writing the transformation in terms of LambertW gives something else, if I'm not mistaken.

I came across what looks to me like an error in Maple 2023.  If it stands alone, Maple evaluates z^0/0! to 1, but inside the sum command it appears to evaluate the same expression to 0.

Download Weird_sum_behaviour.mw

Does Maple handle .graphml files correctly?  When I tell Maple to export a weighted graph as Example.graphml and then import it, the edge weights come back lower than before. 

How i can calculate invlaplace?

iman1.mw

Download iman1.mw

Could someone provide me with the references used when implementing the Statistics:-PredictiveLeastSquares function?

TIA

What is the simplest way to direct all Maple output, and only Maple output, into a PDF?  

My preference would be to include a command at the beginning of a worksheet so that causes all output returned by Maple, print and graphics, to be directed to a named PDF.  Does such a command or set of commands exist, and if so, what is the process to get it to work?

An alternative is to have a command at the end of a worksheet that causes Maple to print the worksheet to a PDF.  Does that exist, and if so, what is it?

Hi everyone,
Please I need your help, if anyone has idea of using Perturbation Theory to Solve the following Logistic Fractional Equation and ploting with iteration. Thanks

Restart

u(t):=1/(m)(u(t)-(u^(2)(t))/(k));

NULL

uu(t):=(k*u_0)/((u_0+(u_0)*k)*(e)^(-t/(m)))

NULL

u(0) = u_0

NULL

In the Grading Quiz, it is possible for students to indicate whether the answer is correct or incorrect. In the context menu, it is also possible to add an icon instead of the text.

For some reason, I can't get this to work! If I assign an icon to the correct answer, the same icon is transferred to the incorrect answer.

Is there a way that I'm missing that can show two different icons rather than the same one?

GraphTheory:-GraphEqual says that G₁ and G₂ are equal, but GraphTheory:-AllPairsDistance gives different results instead: 

Download allpairs.mw

So, which one is incorrect? Any reasons?

that in Kip Thorne's book Maple is mentioned through out ?

Kip Thorne and Roger Blandford : "Modern Classical Physics: Optics, Fluids, Plasmas, Elasticity, Relativity, and Statistical Physics"

also, courtesy of Caltech in Chapter 24

restart;
alias(u = u(x, z, t), f = f(x, z, t));
                              u, f
u := (f+sqrt(R))*exp(I*R*x);
                    /     (1/2)\           
                    \f + R     / exp(I R x)
pde1 := I*(diff(u, z))+diff(u, x, x)+diff(u, t, t)+u*abs(u)*abs(u)-(u*abs(u)*abs(u))*abs(u)*abs(u);
    / d   \              / d  / d   \\           
  I |--- f| exp(I R x) + |--- |--- f|| exp(I R x)
    \ dz  /              \ dx \ dx  //           

           / d   \                /     (1/2)\  2           
     + 2 I |--- f| R exp(I R x) - \f + R     / R  exp(I R x)
           \ dx  /                                          

       / d  / d   \\           
     + |--- |--- f|| exp(I R x)
       \ dt \ dt  //           

                                                            2
       /     (1/2)\                           2 |     (1/2)| 
     + \f + R     / exp(I R x) (exp(-Im(R x)))  |f + R     | 

                                                            4
       /     (1/2)\                           4 |     (1/2)| 
     - \f + R     / exp(I R x) (exp(-Im(R x)))  |f + R     | 

simplify(%);
         / d   \              / d  / d   \\           
       I |--- f| exp(I R x) + |--- |--- f|| exp(I R x)
         \ dz  /              \ dx \ dx  //           

                / d   \                 2             
          + 2 I |--- f| R exp(I R x) - R  exp(I R x) f
                \ dx  /                               

             (5/2)              / d  / d   \\           
          - R      exp(I R x) + |--- |--- f|| exp(I R x)
                                \ dt \ dt  //           

                                               2  
                                   |     (1/2)|   
          + exp(I R x - 2 Im(R x)) |f + R     |  f

                                               2       
                                   |     (1/2)|   (1/2)
          + exp(I R x - 2 Im(R x)) |f + R     |  R     

                                               4  
                                   |     (1/2)|   
          - exp(I R x - 4 Im(R x)) |f + R     |  f

                                               4       
                                   |     (1/2)|   (1/2)
          - exp(I R x - 4 Im(R x)) |f + R     |  R     
collect(%, exp(I*R*x));
  /  (5/2)       / d   \      2       / d   \   / d  / d   \\
  |-R      + 2 I |--- f| R - R  f + I |--- f| + |--- |--- f||
  \              \ dx  /              \ dz  /   \ dx \ dx  //

       / d  / d   \\\           
     + |--- |--- f||| exp(I R x)
       \ dt \ dt  ///           

                                          2  
                              |     (1/2)|   
     + exp(I R x - 2 Im(R x)) |f + R     |  f

                                          2       
                              |     (1/2)|   (1/2)
     + exp(I R x - 2 Im(R x)) |f + R     |  R     

                                          4  
                              |     (1/2)|   
     - exp(I R x - 4 Im(R x)) |f + R     |  f

                                          4       
                              |     (1/2)|   (1/2)
     - exp(I R x - 4 Im(R x)) |f + R     |  R     
 

Hi Dears

I need some random zero-dimensional binomial ideals (20 ideals or more) with two, three, or four ... generators with 4 variables atmost. Then I want to regenerate each of them such that some of their generators are not binomial and the obtained ideals are equal to the first corresponding original binomial ideals. How can do I this automatically?

As a simple example let I be an ideal generated by {x-1, y-1, z-1} which is zero-dim. We can obtain J=<x-z, x+z-2, y+z-2> that is equal to I.

Thank you in advance.

When I try to enter units using the units palette Maple Flow 2023.1 will erase the numerical value entered. That never happened before in previous releases of Maple Flow. No problem if you enter the units yourself, the problem is when you use the units palette. What is going on? A couple of weeks ago I also posted a question about not beeing able to enter an equal sign when entering a math expression in a text region. Agai, this never happened before in previous releases of Maple Flow. What is happening? Am I doing something wrong?

Since I began to use Maple for teaching back in 2014 (now on 2023 version), the following happens to some students. 

While they are in math mode, the Maple engine suddenly stops being unable to do anything (even 2+2). Only way to solve this is to start a new document or restart Maple. I have seen this issue on both Mac and PC version. 

So my question is what causes this?