Hello everyone

I have the following probability distribution, where x ranges from zero to infinity:

with(Statistics):

X := RandomVariable(Distribution(PDF = unapply(piecewise(And(0 < x, x < infinity), exp(-6)*6^x/x!), x)))

How do I tell Maple that this distribution is discrete?

Regards,

Oliveira

The following problem is old and quite challenging. I found it in a publication from 1959. I have the source and my own solution. I was able to solve it quite laboriously a few years ago using MC14 – but not recently with Maple. Therefore, I'm interested in instructive Maple solutions, just as previous puzzle solutions here have helped me further in using this software. I thank you for that.

A wolf observes a goat. It is grazing in a meadow, tied to a rope. Naturally, he wants to catch the goat and considers whether his starting position is favorable. He estimates that he and the goat will be moving at the same speed at the beginning of the hunt and throughout the pursuit, and that the goat will constantly hold the rope taut to maintain its distance for escape reasons. Now, as he approaches the goat at a constant top speed, the same speed as the goat is fleeing in a circular arc, he asks himself: Where do I need to start from to guarantee success? Are there starting positions that rule out a successful hunt? What happens if I manage to sneak into the grazed area first?

i did for two of them base on the information but one of them is not make my odetest to be zero? where is problem

test.mw

I have already plotted the Nusselt number as a line graph. Now, I would like to plot it as a bar graph instead of line graphs. Specifically, I want to create grouped bar charts that combine several parameters (such as Gr, Rb, N[t], N[r], M, Sc) in a single figure. Each group should correspond to one parameter, with bars representing distinct values (e.g., 0.1, 0.4, 0.6, 0.8). For reference, I have attached a sample figure from another work. Could anyone please help in this regard?

Group_bar_graphs_help.mw

In the plane, the concentric circles k1 and k2 are given with center M. Circle k1 is the unit circle (radius = 1), and k2 has twice the area of ​​k1. From the outside, five congruent circles k3 are placed tangent to k1, each with a radius r yet to be calculated. Prove that the circles k3 can be arranged such that any two adjacent circles k3 and k2 can have a common intersection point, and these intersection points form the vertices of a regular pentagon. The radius r is to be calculated exactly (no approximation) as a term.

Suppose I have a metric g, and I want to perform a conformal transformation g = exp(2Phi(X))*g, is there a straightforward way to do this for curvature quantitieies (Christoffel, Ricci Scalar etc)? I was able to do it rather easily for the Christoffel symbols, as seen below, but it required me making a substitution for each index pair. While this isn't horrible, it would be nice if there was a way to do it without this procedure.

** Edited to make it Phi(X) 

Any thoughts appreciated, thank you!

MyConformal.mw

It is possible to perform the simplest QFT calculations with second quantization, in Maple? Bosons in a box. See attached example. bosons_in_a_box.mw

Sure any general purpose programming language is capable of performing this task with enough effort. What I am interested in is if the physics tools has a standard way of dealing with these calculations. The general impedement when attempting the calculation is that integrations are perfomed by replacements with delta functions or kronecker delta functions, and its not clear how to force the Maple Physics package to recognize this or if that's possible. Part of the problem is that integrations in maple are defined in one dimension at a time where as in QFT the integration element is almost always atleast three dimensional, d^3x or dxdydzy, the later of which can get extremely cumbersome with even a small number of fields under consideration. I don't find much of what I am refering to mentioned in the help pages and I doubt these types of QFT calculations are possible to perform in Maple without addressing these issues.

bosons_in_a_box.mw

Hello everyone!
I have had an issue for the past weeks, where it seems like Maple has a problem identifying the correct units and also sometimes having an issue with defining a variable.

In the picture below you can see I have defined rho, m and tried to Solve V. I get m^3, which is fine but I cannot change the unit in the right bar (see picture).

I even tried to just take square root of my V to see if I could then change units. It seems like it thinks I'm playing with weight.
I even had 2 teachers trying to help me find a solution, without luck.

I have tried executing the whole document and also only bits of the document without luck.

Does anyone know this problem and has a solution?

Thanks in advance! 

- Jacob

Hi 
How can I plot f3=0 for different values of Tch and qc?

1.mw

For the derivation of the results that I need for my research, I use advanced calculus, special functions etc.

Consider a derivation of the form LHS = RHS1 = ... RHSn.

Suppose that I have a LaTeX file describing this derivation, with fine details of the derivation in notes written using pencil on paper. 

To check this derivation for errors, such as a wrong sign, I could retype LHS and RHSn into Maple and check for equality using symbolic algebra.

To provide a more detailed check of this derivation, I could type LHS, RHS1, ..., RHSn into Maple and check the sequence equalities LHS = RHS1, ..., RHS(n-1) = RHSn using symbolic algebra.

However, this is a laborious and, itself, an error-prone process.

Is there some way of submitting my LaTeX file (or its compiled version) and/or an image of my handwritten notes for checking by Maple, line-by-line, using symbolic algebra?

It's disappointing that after all these years, Maple still hasn't implemented a real sinc() function, in which an expression with a trig expression(s) can be entered as an argument, with a return value that is expressed as a sinc() function(s), not a return of sin() functions, which is what I get when I try to define my own sinc() function. I find that the Sinc function in the DynamicSystems package to not be very useful for general Maple calculations.

The following code converts an expression containing a trig function to a sinc-function expression. How can this code (or some other code) be implemented in Maple by defining a real sinc function that accepts an expression in its argument and returns an evaluated sinc function, not a return value that has sin functions?

eval(expr, {sin = (x -> x*sinc(x)), 
              cos = (x -> (x+Pi/2)*sinc(x+Pi/2)),
              tan = (x -> x*sinc(x)/(x+Pi/2)/sinc(x+Pi/2))});

Attribute: This code was originally posted by Robert Israel

Thanks for any assistance.

i don't  know  why my graph make a problem and what is issue i did plot  but this time make issue for me which i don't know where is problem there is anyone which can help and even modified the plot?

explore-chaotic.mw

i try to use explor option but is not work like i want and i try to use other way but they so classical i want to ask there is any other way for do plotting of this kind of function?
in second part even plot not working?

Bgraph1.mw

These are current collections of Maple bugs before I lose track of them. I put them all in one post. Hopefully these can be fixed in Maple 2025.2. For each problem, I post separate worksheet, so there are few worksheets here.

This is all on Linux using 2025.1 and latest SupportTools and latest Physics.

1. Random crashes. This one is very strange. The crash happens randomly. You might need to try few times to see it or close the worksheet and reopen it.
 

Download random_crashes_sept_8_2025.mw

2. collection of bugs from solve(identity) (another one related to solve(identity at end)

Download collection_of_maple_internal_errors_sept_6_2025.mw

3. Adding Physics:-Setup(assumingusesAssume = true): make combine fail

Download adding_Phsyics_makes_combine_fail_sept_6_2025.mw

4. odetest internal error when adding assuming

Download internal_odetest_error_sept_6_2025.mw

5. solve(identity,..  gives internal error when one variable is missing

Download missing_variable_solve_sept_6_2025.mw

6. odesteps gives internal error (was question before, moved it to here, so all in one place)
 

Download internal_error_ODESteps_sept_2_2025.mw

Hi everyone

I have the following list:

L:=[[F[1], F[2], F[3], F[4]], [F[1], F[2], F[3], M[1]], [F[1], F[2], F[3], M[2]], [F[1], F[2], F[3], M[3]], [F[1], F[2], F[3], M[4]], [F[1], F[2], F[4], M[1]], [F[1], F[2], F[4], M[2]], [F[1], F[2], F[4], M[3]], [F[1], F[2], F[4], M[4]], [F[1], F[2], M[1], M[2]]

How do I select only the subsets in which the four elements have different indices? For example, I don't want [F[1], F[2], F[3], M[1]] Regards,

Oliveira