I want to check whether the solution trial_sol satisfies the following PDE by Maple:

restart:
PDE:=diff(diff(u(x,y,t),x,y)/u(x,y,t),t$2)-diff(diff(u(x,y,t),x,y)/u(x,y,t),x$2)+2*diff((u(x,y,t)^2),x,t);
trial_sol:=(x,y,t)->sqrt(r)*tan((-t*v+x+c*y) *abs(sqrt(r)/(sqrt(2*c-2*c*(v^2)))))/(sqrt(2)*sqrt(v));
pdetest(u(x,y,t)=trial_sol(x,y,t),PDE);

Maple says the trial_sol is not a solution for PDE.

But Mathematica says that it is a solution. What is the problem?

I plotted the following tangent function with Maple and Mathematica for t=4. 

restart:
func:=unapply(-tan((-4*t+x+2*y)/(2*sqrt(15)))/(2*sqrt(2)),x,y,t);
plot3d(func(x,y,4),x=-15..15,y=-15..15);

Maple 3D plot:

Mathematica 3D plot:

I think that Maple shows the asymptotes. Is it possible to close the asymptotes?

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 need to treat Eqs. (1.85-1.86) as a system of equations that should be solved simultaneously, and use numerical solutions in Eqs. (1.87-1.90)
Do you know if there are in-built commands that can do this?

It's ok isolate command? I need the solution sin(a)=+-1/(3^0.5)

attach photo, i need simple step after 2.78 like book, solution is sin(a)=+-1/(3)^0.5.

Dear all

I try to understand why maple does ot plot the behavior of x^1/3 for negative real number, 

inverse_function_xthree.mw

root(x,3) is function defined verywhere, but why maple plot only this function for x positive 

thank you

The Putnam 2020 Competition (the 81st) was postponed to February 20, 2021 due to the COVID-19 pandemic, and held in an unofficial mode with no prizes or official results.

Four of the problems have surprisingly short Maple solutions.
Here they are.

A1.  How many positive integers N satisfy all of the following three conditions?
(i) N is divisible by 2020.
(ii) N has at most 2020 decimal digits.
(iii) The decimal digits of N are a string of consecutive ones followed by a string of consecutive zeros.

add(add(`if`( (10&^m-1)*10&^(n-m) mod 2020 = 0, 1, 0), 
n=m+1..2020), m=1..2020);

       508536

A2.  Let k be a nonnegative integer.  Evaluate  

sum(2^(k-j)*binomial(k+j,j), j=0..k);

        4^k

A3.  Let a(0) = π/2, and let a(n) = sin(a(n-1)) for n ≥ 1. 
Determine whether the series   converges.

asympt('rsolve'({a(n) = sin(a(n-1)),a(0)=Pi/2}, a(n)), n, 4);

a(n) ^2 being equivalent to 3/n,  the series diverges.

B1.  For a positive integer n, define d(n) to be the sum of the digits of n when written in binary
 (for example, d(13) = 1+1+0+1 = 3). 

Let   S =  
Determine S modulo 2020.

d := n -> add(convert(n, base,2)):
add( (-1)^d(k) * k^3, k=1..2020 ) mod 2020; 

        1990

Hi again. I have been stuck on this for almost 3 hours by now, and i have ran out of ideas..

I am working on a proof called dandelin spheres, which proves you can get an ellipse by cutting a cone with a plane.

I have found the right equation for both semi circles, the line (cone) and the plane.

I have defined the spheres as semi circles, and the cone as a line, which i am plotting by using the surface of revolution command.

The problem lies within the fact, that i cannot use the intersectplot command with surface of revolution, and i need the plot to show the intersection between the plane and cone. 

The following shapes are defined:

cone line - f := x -> 0.5*x;
small sphere - g := x -> sqrt(0.8944271908^2 - (x - 2)^2)

bigger sphere - h := x -> sqrt(3.354101965^2 - (x - 7.5)^2)

plane - m(x, 0) := 1.216350358*x - 3.841106394

with the following command i recieve this output, which i nice, but i am missing the final part, the ellipse.

I hope someone can help a desperate student :)

- Oscar

Hello, everyone!

I have a problem. Colleague send me a figure in maple-file – .mw. How to export data from this plot? I usually use "plottools:-getdata" command, but what strategy should I apply in case of attached file?

Test-example.mw

Dear all,
I want to create a superscripted and subscripted variable in 1-D math. I know that I can establish a subscripted variable by using double “_”, for example, the execution of the following command causes assignment 2 to u__b, in which b is the subscript of u.
u__b:=2;
However, I don’t know any way to create either a superscripted variable or a variable having both the subscript and superscript in 1-D math.
Can anyone help me?
 Best wishes

Dear MaplePrimes community,

I'm trying to calculate the (Moore-Penrose) pseudoinverse of a matrix using the following code:

with(LinearAlgebra):
Identity := Matrix(2, 2, [[1, 0], [0, 1]]):
A := Matrix(2, 2, [[0.5661180126, 0.4338819876], [0.8316071431, 0.1683928571]]):
MatrixInverse(Identity - A, method = pseudo)

Unfortunately, the output appears to be meaningless (and it conincides with what I'm getting by calculating a simple matrix inverse using "MatrixInverse(Identity - A)"). Am I missing something? (And how do I calculate the (Moore-Penrose) pseudoinverse of the matrix (Identity-A)?)

Presenters:

Affiliated Research Professor Mohammad Khoshnevisan

Physics Department, Northeastern University

United States of America

&

Behzad Mohasel Afshari, Admitted Ph.D. student

School of Advanced Manufacturing & Mechanical Engineering

University of South Australia

Australia

Note: This webinar is free. For registration, please send an e-mail to m.khoshnevisan@ieee.org. The registration link will be sent to all the participants on April 26, 2021. Maximum number of participants =60

Vibrational Mechanics - Practical Applications- Animation 1

Vibrational Mechanics - Practical Applications- Animation 2

Vibrational Mechanics - Practical Applications- Animation 3

Special characters like æ,ø,å are causing some troubles when used in Maple Code attachments in workbooks.

I've managed to get around the problem by using HTML equivalents in the first run, but then this will cause problems when exporting the same strings to Excel.

Funnily this problem just arises in Workbooks, not when using the same code in a code edit region.

Special.zip

Rotating Disk(Click to Play the Movie)

Natural Frequency(Click to Play the Movie)

Hanging Mass(Click to Play the Movie)

Rotating Pendulum(Click to Play the Movie)

Cross Over a Bumper(Click to Play the Movie)