Unanswered Questions

This page lists MaplePrimes questions that have not yet received an answer

The model of fixed-bed adsorption column

Fluid phase:

PDE:= diff(U(x, tau),tau)+ psi*Theta*diff(U(x, tau),x)-(1/Pe)*psi*Theta*diff(U(x, tau),$(x, 2))=-3*psi*xi*(U(x, tau)-Q/K);

 

IBC:={U(x, 0) = 0,U(0, tau) = 1+(1/Pe)*(D[1](U))(0, tau),(D[1](U))(1, tau)=0};

Particle:

PDE:= diff(Q(r, tau), tau) = diff(Q(r, tau), $(r, 2))+(2/r)*diff(Q(r, tau),r);

IBC:={Q(r, 0) = 0,(D[1](Q))(0, tau) = 0,(1/K)*(D[1](Q))(1, tau)=xi*(U-Q(1, tau)/K)};

Pe:=0.01:

psi:=6780:

Theta:=3.0:

xi:=10000:

I will really appreciate your help. Thanks in anticipation.

Hi,

     I'm trying to numerically solve a PDE in Maple for different boundary conditions, however I'm having trouble even getting Maple to numerically solve it for simple boundary conditions.

I have cylindrical coordinates, r, z, theta, and I treat r = r(z, theta) for convenience to plot my solution surface. The initial coundary condition is that at z = epsilon (z = 0 is singular) , r = constant and of course r is periodic in theta. This is just a circle, and the analytical solution is know to be a half-sphere  r = sqrt(R^2 - z^2). I entered my initial boundary conditions into Maple, but it doesn't like the periodic one

IBC := { r(epsilon, theta) = R - epsilon__r,
              r(z, 0) = r(z, 2*Pi) };

pdsolve(
  PDE,
  IBC,
  numeric,
  indepvars = [z, theta],
  time = z,
  range = 0..2*Pi);
Error, (in pdsolve/numeric/par_hyp) Incorrect number of boundary conditions, expected 2, got 1

I'm not sure how to make this work, and then generalize it to more arbitrary intial slices r(epsilon, theta) = f(theta).

Here's the attached worksheet, ForMaplePrimesSUbmission.mw

Any help is appreciated,

Thanks

of a square matrix having its entries 1,2,...16? See http://oeis.org/A085000 for info.

I can;t seem to get DSOLVE working.  Will some kindly soul please send me a complete example, starting with an f(x) & clearly documented?   Many thanks.

 

 

AB

Hello,

On my multibody model, I meet a mistake during the simulation which is the following :

"Constraint projection failure at 10s".

1) Do you have a idea on this error message so as to correct the settings for the simulation?

2) I would like to know more about the projection method. If, I'm not wrong, there is not a lot of documentation about the projection method used in Maplesim. 

   a) Does someone have some references (scientific papers) which present the theory used for the projection method in Maplesim?

   b) In ths sense, I would be very interesting about learning the theory of the projection method in order to be able to tune correctly the following options linked to the projection method :

- Projection Iterations
- Projection Tolerance
- Event Projection
- Event Iterations
- Event Hysteresis

Thanks a lot for your help.

Hello,

In my mechanism, I use absolute coordinates.

For the rotation (namely the initial angles/ angular velocites), I didn't see the difference between Inboard and Euler.

It seems to me that in the two cases, the initial angles are defined with regard to the inertial frame and for both, different kind of rotations can be defined.

Have you some ideas on these two options ?

Thank you for your help.

 

 

PS,
PiFast43 is freely available at,

http://numbers.computation.free.fr/Constants/PiProgram/pifast.html

 

 

 

i dont know what`s wrong with it help me guys

hi,

 

I am trying to implement some data-intensive algorithms like: comuting similarity scores, clustering etc. How efficient Maple is in doing these operations? I mean is it comparable to MATLAB in these operations? What toolboxes are useful in these? I am trying to build a recommender system.

 

I am using Maple18 and not sure if Maple has any advantage in implementing these type of algorithms over MATALB??

 

thanks

siba

Hi all.

I am using Maple2015.

I typed in as input y=x/sqrt(1-x^2).

I hit enter.  The output is:

 y=x/sqrt(1-x^2)

I know the 2 answers are equivalent.

My question is why did Maple swap 1-x^2 to -x^2+1???

Any advice to swap it back would be greatly appreciated.

How to find asymptotic behaviour of a function.

For example at infinity

sinh(x) behaves as 1/2*exp(x)

1/sinh(x)  behaves as 2*exp(-x)

exp(-x)*(exp(-x)+1) behaves as exp(-x)

so that it works with a more complex expression.

Hello,

I'm very interested by this function so as to export my code Maple as MATHML thanks to the function ExportContent.

However, this function can be applied only to a expression.

I would like to apply to all the code of my worksheet.

Do you have some ides to apply ExportContent or equivalent to obtain the MATHML transformation of a whole worksheet ?

Thanks a lot for your help.

Best regards,

Hello,

I need to prepare for a final exam for a introdutory computer science course in Maple.
My professor gives us mutliple choice questions, short answer questions and wiritng some codes.

what is the most efficient way to study for my final exam? or how should i study for an computer science exam. I am not really use to preparing for such a course. 

Are there any websites that i can practice multiple choice questions?

I would appreciate any advice.

 

Thank you very much.

Hi. I am having trouble with maples command "Cross product", i don't know why it doesn't work. Can anybody help me? This is a screenshot of the problem:

This question is 99% similiar to an previously posted question, but this one has a little twist(s).

 

http://www.mapleprimes.com/questions/200101-Solving-For-Coefficients-Of-Polynomial-Equations

 

Here is the sample problem. Let's say I have the following equations

 

e1:=(a+b+1)x^2 + (a+1)*x^4 = 0;

e2:=(a-b)*x+ (a^2 - 1)*x^3 = 0;

 

One can immediately tell the system is inconsistent because on x^3, we have a = -1,1 but on x and x^2 we have a = -1/2

This is precisely the problem I am facing, my e1 and e2 will eventually get bigger (bigger as in the order of the polynomial will increase) and I keep facing inconsistencies.

However if I could find a way to code it so that I can ask Maple to solve only up to a certain degree it would be great. This will eliminate any inconsistency

 

For example, using the system I have here, the system is consistent up to order 2 (it will always start from constants and up to a certain power). So I will ask Maple to solve the above system up to order 2.

Here is a pseudocode I have been working on.

 

For i = 1..2 //this might be increased, but it will of course be finite and probably won't go past 10.

For j = 0..N


//N is the degree of polynomial

f[i]:= coeff(e[i],x,j);

end

end

 

//the above generates the equations, below will solve it

 

solve( { f[i], i=1..?} ,{a,b})

 

Note that the pseudocode assumes e[i] are expressions and not equations set to 0 (which is what I have). Is there an "un"unapply on maple?

 

edit1: have to sleep  (late where I am! Will check for responses tomorrow) thank you

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