## email notifications not working: Is it only me...

For a month I did do not get email notfications.

I checked spam folders, settings and email filters.

Is it only me?

## How to do Parameter setting?...

The attached sheet contains equations H1 to H6 and K1 to K3. What data do I need to modify to ensure that the values of H1 to H6 fall between 0 and 1, and K1 to K3 are negative? The parameter ranges are also given in the sheet. Is there a method to achieve this?

rouhg.mw

## Set up equation for finding parameter and do odete...

i did two case of this equation and odetest is worked good but in this case the odetest is not worked well anyone can determine what is mistake ?

F_P_Correct_case_three.mw

## Error in Display the plots...

Dear Maple user I am facing error while running the codes  to plot the graph for two data sets .

I am attaching the files.

Error_in_Display_1.mw

## A general question about dsolve...

Why does dsolve not call odetest by default before a solution is returned?

I mean, why do I have test each result separately. dsolve could have an odetest option (default=true).

In case of discrepancies dsolve could inform the user and suggest to call dsolve with odetest=false and run odetest separately to analyse the problem.

Set up this way, dsolve would never return potentially incorrect solutions that do not pass odetest.

## How to plot heat transfer rate for this problem?...

HTR.mw

In above problem, Additionally How to  plot  heat transfer rate  Q versus L^2  for distinct porosity parmeters(Sh) , using  heat transfer rate formula, Q = (q*L)/(k*A*T[b])=theta'(1).

using  [Sh = 0.1, L^2 = 0.1, Nr =0 .1, Ha =0 .1, Pe = 0.1],  [Sh = 0.3, L^2 = 0.3, Nr = 0.1, Ha = 0.1, Pe =0 .1],   [Sh = 0.5, L^2 =0 .5, Nr =0 .1, Ha = 0.1, Pe =0 .1].

## How can I find Mean, Median, Quartiles, Variance, ...

How can I find Mean, Median, Quartiles, Variance, StandardDeviation of data in this table

I use Mathamatica and get the result

Clear["Global*"]
boundaries = Range[0, 10, 5/2];
frequencies = {18, 11, 13, 6};
binMeans = Mean /@ Partition[boundaries, 2, 1];
weighted = WeightedData[binMeans, frequencies];
weightedHist = HistogramDistribution[weighted, {5/2}];
Through[{Mean, Median, Quartiles, Variance, StandardDeviation}[
weightedHist]]

## is it safe to update Physics while Maple is busy r...

I have number of worksheets open. I set each to use its own engine.

If I have one worksheet running a long loop that takes hrs to complete, or even if I have cmaple.exe running long script in command line, and then at same time I open new worksheet and type

Physics:-Version(latest)

Then I always get this error

This is described here

It seems because Maple was busy running another worksheet. I never see this error if I am not running any other thing in Maple at the time. ( I actually try not to update Physics while running something else in Maple, but sometimes I do not notice that I have something else running).

When I wait for my other worksheet to finish, then close all of Maple and reopen Maple, I see the latest version is installed, at least this is what Physics:-Version() now says.

My question is:  Is it safe to do Physics:-Version(latest) even when Maple is busy running  computation in other separate worksheet or even running cmaple.exe from windows command line? Is there any concurrency/locking issue on the Physics library being updated while it is being open by another worksheet or another server.exe running in background?

All this is on windows 10 pro.

## Has Select Quaestion...

I trying to simplify expressions for lines so no higher order terms. factor and op seperate out what I need but how do I select the one with the variables in this case x,y. I cant depent on this always been the last one returned from the op command.

 > restart
 >
 > vars=[x,y]
 (1)
 > k:=17
 (2)
 > expr:=-2*sqrt(118)*(((-4*x + y + 51/32)*sqrt(k) + (k*x)/4 - (51*y)/4 + 153/32)*sqrt(-4012 + 1003*sqrt(k)) + ((x + 4*y)*sqrt(k) - (85*x)/4 - (17*y)/4)*sqrt(4012 + 1003*sqrt(k)))*k^(1/4)/(17051*(-1 + sqrt(k)))
 (3)
 > indets(expr)
 (4)
 > factor(expr)
 (5)
 > op(factor(expr))
 (6)
 > select(has,vars, factor(expr))
 > select(has,vars, op(factor(expr)))

## How find Lie symmetry of this equation ?...

I get my on results but the results are not the same please help me if i did any mistake in my code

symmetry_PDESYS_3_time_fraction[1].mw

## Canonical equation of a conic...

This code is working for function f1 but not for f2
f2 := (x,y)->9*x^2-24*x*y+16*y^2+10*x-70*y + 175;
Why this code is not working for f2 ?
unprotect(D);
f1:= (x, y) -> 3*x^2 - 3*y*x + 6*y^2 - 6*x + 7*y - 9;
coeffs(f(x, y));
A, B, C, D, E, F := %;
theta := 1/2*arctan(B/(A - C));
solve({-2*A*xc - B*yc = D, -B*xc - 2*C*yc = E});
assign(%);
x := xcan*cos(theta) - ycan*sin(theta) + xc;
y := xcan*sin(theta) + ycan*cos(theta) + yc;
Eq := simplify(expand(f1(x, y)));
xcan^2/simplify(sqrt(-tcoeff(Eq)/coeff(Eq, xcan^2)))^2 + ycan^2/simplify(sqrt(-tcoeff(Eq)/coeff(Eq, ycan^2)))^2 = 1;

Thank you

## Maple 2024 ellipsis (three dots) in 3x4 matrix onl...

In Maple 2024, using commands like
with(LinearAlgebra):
M := Matrix([[1, 2, 3, 10], [4, 15, 6, 7], [0, 0, 0, 0]]);
ReducedRowEchelonForm(M);

we see output of the 3x4 matrices fine at first, but when I and my students try to print or save to a PDF, ellipsis (three dots) sometimes show up in the bottom row. I checked the settings for elision and they are as usual. This is only when trying to print---the ellipsis show up in both the Maple file and the printed copy. We've tested on both Mac and PC. This did not happen in Maple 2023.

I have side-by-side comparisons in an image below: the Maple looking fine before we try to print or save as a PDF, what happens in the Maple file after with the bottom row, and the elision settings. Any help would be greatly appreciated as we would like the full matrices to show up in printing or a PDF we save to.

## Error in Solving System of ODEs: "System must be e...

I'm trying to solve a system of coupled differential equations numerically, but I'm getting the following error

Error, (in dsolve/numeric/process_input) system must be entered as a set/list of expressions/equations

The error occurs at the dsolve` step, despite trying to ensure that all equations and conditions are in the correct form (sets/lists).

Could someone help me identify what I'm missing here?

## Maple returns solution to ode with no solution?...

Why Maple returns y(x)=0 as solution to this ode when even odetest do not validate the solution? Solution satisfies the ode but not the given BC.

Is this a known bug?

I've updated the worksheet now to include few more examples, all using same ode but with different BC's. In all 4 examples, Maple gives solutions when there should not be solution and in one case gives solution which can not even be used for odetest. These are random BC's generated just for testing.

 > interface(version);

 > Physics:-Version();

 > libname;

 > restart;
 > #EXAMPLE 1
 > ode:=diff(diff(y(x), x), x) + 2*diff(y(x), x)/x - y(x) = 0; IC:=y(-1)=0,D(y)(-infinity)=-1/exp(1);

 > maple_sol:=dsolve([ode,IC]);

 > odetest(maple_sol,[ode,IC])

 > restart;
 > #EXAMPLE 2
 > ode:=diff(diff(y(x), x), x) + 2*diff(y(x), x)/x - y(x) = 0; IC:=y(infinity)=0,D(y)(-infinity)=-1/exp(1);

 > maple_sol:=dsolve([ode,IC]);

 > odetest(maple_sol,[ode,IC])

 > restart
 > #EXAMPLE 3
 > ode:=diff(diff(y(x), x), x) + 2*diff(y(x), x)/x - y(x) = 0; IC:=y(-infinity)=0,D(y)(-infinity)=-1/exp(1);

 > maple_sol:=dsolve([ode,IC]);

 > odetest(maple_sol,[ode,IC])

Error, (in signum) signum is not differentiable at 0

 > #EXAMPLE  4
 > restart;
 > ode:=diff(diff(y(x), x), x) + 2*diff(y(x), x)/x - y(x) = 0; IC:=y(-infinity)=0,D(y)(infinity)=-1/exp(1);

 > maple_sol:=dsolve([ode,IC]);

 > odetest(maple_sol,[ode,IC])

 >

Update sept 13, 2024

Here is one more example I found. In this ode, the IC given leads to division by zero in the solution. Yet Maple for some reason removes the offending part of the solution with that constant, and returns the rest.

Is one allowed to do this? odetest also do not validate the solution. There should not be solution returned in this case, since it is not possible to find values for the constants of integration given these initial conditions. Right?

 > interface(version);

 > restart;
 > ode:=x^2*diff(y(x),x\$2)+x*diff(y(x),x)-9*y(x)=0; IC:=y(0)=1,D(y)(0)=0; maple_sol_no_IC:=dsolve(ode);

 > maple_sol_with_IC:=dsolve([ode,IC]); #maple just removed the c2/x^3 part. Since at x=0 gives problem?

 > odetest(maple_sol_with_IC,[ode,IC]); #shows solution does not verify

 >