Hi,

I want to solve a first order ODE and (i) plot phi vs. x and then (ii) export data of the plotted curve as an T-shape ASCII file. I try to do this by Maple, but there are some errors and I couldn’t get the mentioned curve and ASCII file. Please, help me to remove errors:
(dphi/dx)**2+2*V(phi)=0,

where V(phi)= (1-alpha)*M^2 - (1-alpha)*M*sqrt(M^2 - 2*phi) + mu*(mu + beta*nu)*(1 - exp(phi/(mu + beta*nu))) + 
            (nu/beta)*(mu + beta*nu)*(1 - exp(beta*phi/(mu + beta*nu))) + (alpha/gamma1)*(1 - exp(-gamma1*phi)),

where we assume mu := 0.01, nu := 1 - mu, beta := 0.05, alpha := 0.3, M := sqrt(0.704), gamma1 := 0.001.
As it is seen from the attached figure, V(phi) and dV(phi)/dx =0 for phi=0 and phi=phi_m (two extreme points of V(phi)) and d^V(phi)/dphi^2<0 at phi=0 and phi=phi_m (phi and x are real). 

From the attached figure, it seems that phi=phi_m at x=0 and phi->0 as x-> infinity. (Hint: I expect the plot of V(phi) vs. phi and phi vs. x be similar to the curve "A" in the attached file).

Thanks.
rk4.mw

i did pdetest without conjugate like the paper did i get zero but when i did pde test  with conjugate i didn't where is my problem 
i will do without conjugate but how change p[2]=conjugate(p[1])

Download p1.mw

I am in the process of trying to learn Maple. As an exercise I am trying to plot an amplitude modulated waveform. No problem plotting the waveform of the carrier and the modulating signal but for some reason (user error on my part) I can't plot the combined waveform y given by. 

y = [1 + M*cos(2*Pi*f__m*t)]*A*sin(2*Pi*f__c*t)

Where the following values have been set M = 0.5, A = 1, f_m = 2, f_c = 10.

Plotting y using the following

plot(y, t = 0 .. 1, title = "Graph of Carrier", labels = ["time (seconds)", "Amplitude (Volts)"], color = red);

Gives the following error. Having tried various combinations of variables, values, single parameter functions etc I need a pointer as to where I am going wrong. 

Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct
What I am expecting is a graph similar to the below derived in Excel? My version of Maple is 2023.2

VC1.mw

How to solve this error?

i don't know how apply conversation language to matlab in righ hand side  don't show up to do conversation language for short is come up but for this not 

Download convert-to-matlab.mw

I have plotted a 3D figure by maple 2023. but all numbers and units on axes are seen a black boxes. How can fix this problem?

Dear Maple Community,

I come to you with a question about the reduced involutive form (rif) package. Namely, I decided to try the classic example from the "LONG GUIDE TO THE STANDARD FORM PACKAGE", which dates back to 1993. Here is the link to the complete documentation:

https://wayback.cecm.sfu.ca/~wittkopf/files/standard_manual.txt

So, the example is the following:

2.1 SIMPLE EXAMPLES

EXAMPLE A

Consider the system of nonlinear PDEs:       

y Zxxx - x Zxyy  =  Zyy - y Zy

                        2     2    2
2 y x Zxxx Zxyy + x Zxxx + x y Zxyy  =  0

                  2    2
y Zxyy - x W + 2 x  y Z  =  0

                 2    2
Zyy - y Zy  + 2 x  y W  =  x W

where the dependent variables W and Z are functions of the
independent variables x and y, and Zxxx denotes the third partial
derivative of Z with respect to x etc.

After making computations back in 1993 with Maple V, they obtain the following involutive form:

In our original notation the (considerably) simplified system is:
                                            2
  Zxxx = 0, Zxy = 0, Zyy = y Zy, W = 2 x y Z

So, I tried the same system of PDEs in the modern Maple and the modern rifsimp() command. You can find the result below:

I demo_question.mw

The problem is that nowadays [Maple 2022.1] , I get only the trivial solution: z = 0 and w = 0.

Could someone clarify, please, where the truth is and what am I doing wrong?

Thanks a lot in advance for any help and clarification!

Best regards,

Dr. Denys D.
 

I have one random variable as follows:  r := sqrt(RandomVariable(Uniform(0,1)))

I have another as follows:  x := cos(RandomVariable(Uniform(0, 2*Pi)));

The r variable returns a PDF of 2*t, where t<1; 0 otherwise.  The variable x returns a PDF of 1/(Pi*sqrt(1-t^2)), where |t|<1; 0 otherwise.

For both random variables, I have validated through simulated values.  I am convinced the above PDF functions are correct.  When I multiply r*x in Maple and then ask for a PDF of the resultant random variable, I fail.  Maple seems to not like this.

My question is then as follows...can anyone help me get the PDF of r*x?

Which version of Maple contains its most optimal and elegant coding, regardless of utility,  and was it the product of someone's direct creative input (not auto-coded with AI for example).

As an aside, there's a spelling mistake in the word "separate" below within the "Tags" instruction:

"Tags are words are used to describe and categorize your content. Combine multiple words with dashes(-), and seperate tags with spaces."

I am making changes in my code in order to make it work with Grid. This involves making many modules I had export on them as local.

I have lots of code of this form

use toX=A:-some_very_long_module_name:-toX in
local B := module() 
       export foo:=proc()
            toX(...);
       end proc;
end module;
end use;

This is done so I do not have to type A:-some_very_long_module_name:-toX() all the time as toX() is a very common call I make all over the place in many different modules.

This was working fine, except when I now changed some_very_long_module_name module to be local.

I really do not want to change all my code and change toX(...) to the explicit fully qualified name  some_very_long_module_name:-toX(....)

I could probably look into using alias instead, but I do not like aliases.

But before doing this, any one knows why this now makes Maple not happy? And if it possible to make use....end use while keep this long named module local?

Below is work sheet showing 4 examples. The first one is how I had things before, where the module was export.

The second and third examples showing the problems that show up when changing the module to local.

The last one showing it works if I remove use...end use and just type the full long name.

my goal is to keep this long named module local, but still use  use...end use. around other modules which needs to make calls to it. Just to safe typing, that is all. 

Any ideas to try are welcome. 

Download trouble_with_use.mw

The following page of the documentation cites an article from the newsletter which I would be very interested in reading: 

- https://www.maplesoft.com/support/help/view.aspx?path=assume

The full citation for the article I'm interested in is as follows:
 

Hello,

I have updated to maple 2024 on both my desktop and my laptop, and now I am missing the feature "Convert Output Units:" in the context tab on my windows 11 laptop. It's still available on my windows 10 desktop.

I have tried reinstalling maple and installing java, but it unfortunately did not help. Due to limited school licences, I am unable to test with maple 2023.

Is this an issue you have heard of?

Thank you in advance,

Daniel

And here is the context menu on windows 11. Also nothing happens when I click "Format -> Convert Output Units" in the top menu. 

Hello, i have been drawing some cool 3d plots for my assignment, but when i use the export button and export it as pdf the plots turn out very low quality. 

See the image below is using the export function

Then i tried something different i tried using the print button and printing to a pdf.

That resulted in a different looking plot

This plot using the print to pdf feature looks much nicer, but the 3d text plot has become impossible to read.

Is there a way to fix that? Or to make the export to pdf feature export at higher quality? 

Best Regards

I have a list of values in the range from 1 to 6 inclusive:

    [> y := [ seq(rand(1..6)(), i = 1..10) ] : # step 1

I would like to replace all elements <= 3 with -1 and all elements > 3 with 1

    [> y := subs(1=-1, 2=-1, 3=-1, 4=1, 5=1, 6=1, y) : # step 2

Then calculate the cumulative sum

    [> y := [ seq(add(y[ .. i]), i = 1..n) ] : # step 3

And plot the results

    [> plot([ seq(i, i = 1..n) ], y) # step 4
 

This all works, but step 2 is downright ugly. Is there a more elegant expression available?

And step 4 requires I generate an extra data set for the x-axis. Is there a way to specify just the the y-values and have Maple assume the x-values are in the range  1..nops(y)? (Something akin to just  plot(y), which produces output I don't understand.)

By way of example, I am trying to replicate this MATLAB expression:

    > y = cumsum(2*(randi(6, 10, 1) <= 3) - 1); plot(y)

restart;
Fig:=proc(t)
local a,b,c,A,B,C,Oo,P,NorA,NorB,NorC,lieu,Lieu,dr,tx:
uses plots, geometry;
a := 11:b := 7:
c := sqrt(a^2 - b^2):

point(A, a*cos(t), b*sin(t)):
point(B, a*cos(t + 2/3*Pi), b*sin(t + 2/3*Pi)):
point(C, a*cos(t + 4/3*Pi), b*sin(t + 4/3*Pi)):
point(Oo,0,0):
lieu:=a^2*x^2+b^2*y^2-c^4/4=0:
Lieu := implicitplot(lieu, x = -a .. a, y = -b .. b, color = green):

line(NorA, y-coordinates(A)[2] =((a^2*coordinates(A)[2])/(b^2*coordinates(A)[1]))*(x-coordinates(A)[1]),[x, y]):
line(NorB, y-coordinates(B)[2] =((a^2*coordinates(B)[2])/(b^2*coordinates(B)[1]))*(x-coordinates(B)[1]), [x, y]):
line(NorC, y-coordinates(C)[2] =((a^2*coordinates(C)[2])/(b^2*coordinates(C)[1]))*(x-coordinates(C)[1]),[x, y]):
intersection(P,NorA,NorB):

ellipse(p, x^2/a^2 + y^2/b^2 - 1, [x, y]);

tx := textplot([[coordinates(A1)[], "A"],[coordinates(A2)[], "B"], [coordinates(C)[], "C"], [coordinates(Oo)[], "O"],#[coordinates(P)[], "P"]], font = [times, bold, 16], align = [above, left]):
dr := draw([p(color = blue),NorA(color=red,NorB(color=red),NorC(color=red),p(color=blue),
Oo(color = black, symbol = solidcircle, symbolsize = 8), P(color = black, symbol = solidcircle, symbolsize = 8)]):
display(dr,tx,Lieu,scaling=constrained, axes=none,title = "Les triangles inscrits dans une ellipse ont leur centre de gravité en son centre . Lieu du point de concours des perpendicalaires issues des sommets", titlefont = [HELVETICA, 14]);
end:

Error, `:=` unexpected
plots:-animate(Fig, [t], t=0.1..2*Pi, frames=150);