## SEEMOUS 2017

by: Maple

Here is a problem from SEEMOUS 2017 (South Eastern European Mathematical Olympiad for University Students)
which Maple can solve (with a little help).

For k a fixed nonnegative integer, compute:

Sum( binomial(i,k) * ( exp(1) - Sum(1/j!, j=0..i) ), i=k..infinity );

(It is the last one, theoretically the most difficult.)

## Print nothing when using a procedure...

**I am trying write a procedure (bit(n,k)) that print all the binary sequences with 2 following conditions:
- Each of the sequences has the length of 'n'. (n elements)
- k bits of n elements have the value 1. (all the remains have the value 0)
Example: bit(3,2) and the result is ((101),(110),(011)).
**My code:
bit := proc (n, k)
local one, index, i, d;
global A;
one := 0;
index := 1;
A := [seq(0, i = 1 .. n)];
d := proc (index)
if one = k or index = n+1 then return NULL; end if;
for i from 0 to 1 do
A[index] := i;
if i = 1 then one := one+1; end if;
if one = k then print(op(A)); end if;
d(index+1);
if i = 1 then one := one-1; A[index] := 0; end if;
end do;
end proc;
d(1);
end proc;
>bit(5,1);
result:
0, 0, 0, 0, 1
That 's not the answer for the excercise. What is the problem?

## How do I solve a simple line integral in Maple?...

Hello there. I have to solve a simple line integral (3*y-x)dL from A(2;1) to B(3;-1). A and B are points in the line described by function y=5-2x. I found a function LineInt. Using paramether Line I wrote LineInt(3*y-x, Line(<2, 1>, <3, -1>)), it doesn't work with error below:

Error, (in Line:-ModuleCopy) invalid input: invalid specification of line

It seems that the problem is with first argument, that is the equation under the integral sign. Or no... How to write it properly? Thanks.

## Maple TA 2016: Lists depopulate in adaptive questi...

I am currently working on an adaptive question in Maple TA 2016 and it seems that there is a bug in the drop - down list functionality:

After I click "Verify" in a section, the answer disappears even though I choose it to be displayed. The window simply goes back to showing (Click for List) instead of keeping the answer, see the screenshot below.

Perhaps I am doing something wrong, though I have used Lists extensively in the previous version and never had that problem ..

Elisabeth

## ODE boundary value problem ...

It is known that ODE boundary value problem is similar to the problem of solving systems of nonlinear equations. Equations are the boundary conditions, and the variables are the values of the initial data.
For example:

y '' = f (x, y, y '), 0 <= x <= 1,

y (0) = Y0, y (1) = Y1;

Where y (1) = Y1 is the equation, and Z0 is variable, (y '(0) = Z0).

solve () and fsolve () are not directly suitable for such tasks. Directly should work the package of optimization in relation to a system of nonlinear equations. (Perhaps it has already been implemented in Maple.)
Personally, I am very small and unprofessional know Maple and cannot do it. Maybe there is someone who would be interested, and it will try to implement this approach to solving ODE boundary value problems?

## Problem with differential operator...

hi.please see attached file below and help me.one problem is apply differential operator on matrix and then caclute 3D integral?

maple2.mw

 (1)

 (2)

 (3)

 (4)

 (5)

 (6)

 (7)

 (8)

 (9)

## Float(undefined) as integral value...

hi.i am a problem with calculate numeric integral.

thanks

## Numerical solution for the N-body problem with...

Maple

Some Maple 18 short (and I believe elegant) code for doing gravitational simulations with N bodies in space:

N_body_problem.mw

Initial velocities have been tweaked to keep the system stable for the duration of the animation.

Please feel free to fiddle with its parameters, velocities and positions and/or N itself, to produce more interesting animations or re-use the code therein (You can safely ignore the (c), it's there just for archiving purposes).

The following are animations from three runs with N=4, N=3 and N=2, no other parameters changed.

## The "Happy Ages" problem...

This is not actually a question, but an interesting problem found in the recent book (2nd edition, 2015):
Mathematica®: A Problem-Centered Approach
by  Hazrat Roozbeh
Springer

I hope that you will enjoy the problem too.

Define the functions f, h : N --> N by
f(n) = the sum of the squares of the digits of n; e.g. f(25) = 2^2 + 5^2 = 29.
h(n) = min {f(n), f(f(n)), f(f(f(n))), ... };  e.g. h(7)  = min{49,97,130,10,1} = 1.

A natural number n is happy if h(n) = 1.
Find all the happy ages, i.e., happy numbers up to 100.
Conclude that happy ages are mostly before one gets a job or after retirement!

## Sliding ellipse problem ...

Has anyone solved this problem from an older Putnam paper?

An ellipse sitting in the first quadrant with its major axis parallel to the x axis is tangent to the positive x and y axes.

It slides clockwise within the first quadrant while maintaining tangency to both positive axes until its major axis is parallel to the y axis.

Prove that the locus of its centre is the arc of a circle.

I have crudely animated this motion by sliding the axes around the stationary ellipse. Is there a more elegant animation which slides the ellipse against stationary axes?

## Problem with plot ...

The plot command outputs a graph of symbols where the line is made up of "H"s, vertical lines on the axes are "+"s, horizontal lines on the axes are "-"s, and intercepts are "*"s.

How do I fix this problem so that the graph displays a graph normally?

## Social Golfer Problem...

Social Golfer Problem

So we have 8 golfers : 2 golfers per group and 4 groups.Over several golfing days, how can they be arranged so no golfer plays with the same player twice.

turns out they can play for 7 days.

So my attempt in maple....golfing.mw

For 3 players per group and 4 groups this is the arrangement over 4 days:

(these was done in wolfram demonstrations project but the code appears to be obfuscated)

Why hasn't mapleprimes yet been able to solve the spam problem.  There was never this long a problem with Mapleprimes 1, every morning I find spam for the last few weeks.

Also the timing still has yet to be fixed.  After 1 hour the times for when a post was made goes back to 0 minutes ago.

## evaluation problem...

LE_EQ.mwWhat is problem with this programme,why it does'nt calculate the values but only shows the solution with integral sign instead of calculating it, there is also arising a problem in plots

## My contact with Maplesoft Customer Service

Maple

On this week I asked Maplesoft Customer Service for help. Here is our correspondence
(Only the purchase code and e-mail addresses are censored. PS. Also the last name of Kari was deleted by Bryon Thur on 28.08.2015.).
I think this is of interest for many Maple users. I have got some experience contacting
with Kaspersky Antivirus (They helped me by the use of indices of my comp.) and ABBYYLingvo
(They helped to install an ABBYYLingvo vocabulary on my phone.) so I can compare and
make conclusions.

From:
Sent: August-15-15 4:44 AM
To: Maplesoft Customer Service
Subject: Customer Service Request: (Web) Installation questions

Hello,
After upgrading my Windows 7 HB 32-bit to Windows 10 I cannot uninstall my Maple 16 PE.
It cannot be uninstalled by neither Start/Parameters/System/Applications nor
Uninstall in C/ProgramFiles/Maple 16.
The Uninstall option is not seen in Maple 16 as application.
Also the overinstallation of Maple 16 does not work.
Sincerely,
Markiyan Hirnyk
------------------------------------------------------------------------------------------------------

Dear Markiyan Hirnyk,

Thank you for contacting Maplesoft.

Maple 16 is not officially supported on Windows 10 but I have added an activation to your
existing Maple 16 Personal Edition purchase code: XXXXXXXXXXXXXXXX to see if reactivating
send me the exact wording of any error messages that you receive so that I can send
the information to our Technical Support Team so that they can investigate further.

Kind regards,

Kari
Maplesoft
Customer Service
-----------------------------------------------------------------------------------------------------------
Hello Kari,
Unfortunately, neither the  reactivation of my Maple 16 PE by XXXXXXXXXX nor its uninstallation
do not succeed for me. See the error communications in the attached screens (both in one file) screens_1_2.docx.
It should be noticed that Maple V Release 4 works on Windows 10 of my comp without any problems.
Regards,
Markiyan Hirnyk

--------------------------------------------------------------------------------------------------------
Hi Markiyan Hirnyk,

I am forwarding your information to our Technical Support Team.
A representative will contact you soon.
Kind regards, Kari
Maplesoft Customer Service
------------------------------------------------------------------------------------------------------------
Hello Markiyan,

This error is usually caused by a Windows permissions setting. To fix this, please do the following:

1. Ensure that all Maple programs are completely closed.
2. Click on your Start Menu and go to the 'Programs' > 'Maple 16' > 'Tools' folder.
3. Right click the 'Activate Maple' icon and choose 'Run as administrator'.
4. Activate Maple using your purchase code and this should fix your issue.

Please let me know if you continue to experience any troubles.

Regards,

Chris
Technical Support Analyst
--------------------------------------------------------------------------------------------------------
Hello Chris,
Following your directions, I have just reactivated Maple 16, but my problem is not solved.
To shed light on the situation, my Maple 16.02 works properly,
but I cannot uninstall it after upgrading to Windows 10 Home 32bit.
See the screens in the attached file screen.docx .
Regards,
Markiyan Hirnyk
----------------------------------------------------------------------------------------
Hello Markiyan,
If you are seeing error messages about Maple still being open,
I would suggest you try to restart your PC and then attempt the uninstall again to ensure
that you do not have any lingering Maple programs running. Please let me know
if you still see this message after restarting.

Regards,

Chris
Technical Support Analyst
------------------------------------------------------------------------------------------------------
Hello Chris,
This does not help too. My guess is execution failure when Maple 16 was installing.
Because of that reason the Maple 16 installer did not create Maple uninstaller in my Maple 16.
See the attached screen of the uninstall folder in C:/ Program Files/ screen_3.docx.
Regards,
Markiyan Hirnyk
--------------------------------------------------------------------------------------------------------
Hello,
If you think that you have a corrupted installation, I recommend that you reinstall Maple
using the new Maple 16.02 installer link provided below.
This version of the installer was created to get around the Windows 8 installation issues and
may be of help to you in Windows 10 as well, though again please be aware that
we do not officially support Windows 10 yet.
Here are the steps to reinstall Maple:
1. Click on the Start Menu > Control Panel > Programs and Features ( or Add/Remove Programs).
Find ‘Maple 16’ in the list and uninstall it. If this is not possible, move on to the next step and continue.
3. Click on the Start Menu > Computer > Local Disk C: > Program Files.
If there is a folder here called ‘Maple 16’, please delete it.
5. Make sure to download the correct version for your operating system, i.e. Windows version and 32 or 64-bit.
6. Install Maple by right clicking the installation file and choosing ‘Run as administrator’.
I hope that this helps to resolve the issues that you’re having and if it does not,

Regards,
Chris
Technical Support Analyst
--------------------------------------------------------------------------------------------------------
Hi Chris,
My problem with Maple 16 is solved. I completely uninstalled it by Uninstall Tool 3.4, not using brute force. After that I installed Maple 16 by the distributive suggested by you. That's all right.
Regards,
Markiyan Hirnyk
---------------------------------------------------------------------------------------------------------
Alright, that is good to hear. Please let us know if you run into any further issues with your installation.
Regards,
Chris
Technical Support Analyst

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