MaplePrimes Questions

Search Questions:

Latest Questions Latest Questions Feed

As title.


While  I can  decide velocity,charge and Distance.





I have three system of ODE and i would like to solve it using Homotopy perturbation method. Could you please provide to me the code in Maple or the Maple pachage that used to solve it by Homotopy perturbation method ?

I hope to hear you soon



Hi there. 

I'm kind of new to Maple and i'm trying to solve a Linear Algebra problem for my class of Linear Algebra of the course of Physics. Also, my first language is portuguese so forgive for my not-so-perfect english.

I have a (solved) linear system of 7 equations and 12 variables (A, B, C, D, E, F, G, H, I, J, K, L) that is the following:

  • A = 33 - K - L
  • B = 1 + F - J
  • C = -15 - F + J + K + L
  • D = 15 + H - K
  • E = 16 - F - H + J + K
  • G = 34 - H - J - L
  • I = 18 - J - K

Note: I'm using letters (A, B, ..., L) instead of X1X2, ..., X12 because it's easier to write it like this here and because I don't know if the Xn notation is allowed on Maple (i don't think so).

So, the system is possible but undetermined (with 5 degrees of freedom), being F, H, J, K and L the free variables.

Until here, everything's fine. The problem arises when the professor asks us for every solution of the system that satisfies the condition that all the variables (form A to L) are positive integers (A, B, C, D, E, F, G, H, I, J, K, L ϵ IN → natural numbers).

From my understanding, that gives rise to a system of linear inequalities with 12 variables and the following inequalities:

  • A = 33 - K - L > 0
  • B = 1 + F - J > 0
  • C = -15 - F + J + K + L > 0
  • D = 15 + H - K > 0
  • E = 16 - F - H + J + K > 0
  • G = 34 - H - J - L > 0
  • I = 18 - J - K > 0
  • > 0
  • > 0
  • > 0
  • > 0
  • > 0                            (and A,B,C,D,E,F,G,H,I,J,K,L ϵ IN)

After some research, i found that a possible way to solve this type of system of linear inequalities is trough a method of elimination (analog to Gauss-Jordan's elimination method for systems of linear equations) named Fourier-Motzkin. But it's hardwork and i wanted to do it on the computer. After some research, i came across with the following Maple command:


So, I tried to use that command to solve my system, with the following result (or non-result):

LinearMultivariateSystem({F > 0, H > 0, J > 0, K > 0, L > 0, 1+F-J > 0, 15+H-K > 0, 18-J-K > 0, 33-K-L > 0, 34-H-J-L > 0, -15-F+J+K+L > 0, 16-F-H+J+K > 0}, [F, H, J, K, L]);

Error, (in SolveTools:-Inequality:-Piecewise) piecewise takes at least 2 parameters

So, i really need help solving this as the professor told us that the first one to solve would win a book, eheh. I don't know what I'm doing wrong. Maybe this Maple command is not made for 12 variables? Or maybe i'm just writing something on a wrong form. I've never used Maple before so i can be doing something really stupid without knowing it.

I would really apreciate an answer, as my only goal as a future physicist is to unveil the secrets of the Cosmos to us all.

Thank you again.

Miguel Jesus


After I have substitute all the variables by hand ,maple still continious  processing(27 hours and still evaluating)for a simple

summarisation by the time that live math2 needed only 2 mins.Have i done something wrong?I want to solve the following equation which is shown in the attached file with the experimental data

OK. Perfect. It runs.

Now, I would like to remove all the set of solutions where for two variables (for example a and b) are negative.

For example, if I have this :

{a=1,b=-1,c=1}, {a=1,b=1,c=1}, {a=-2,b=-1,c=1}

After filtering, I would like to have only :


Thanks a lot for your help.



After a solve on a system composed with trigonometric functions, i obtain several group of solutions.

Here a picture of my solutions :

How can I do to extract from thses solutions only the group composed with real components.

Thanks a lot for your help

I read this, but there was nothing on how to write a help associated with it.

Does anyone know where I can find it?


Many thanks,



I want to draw a contour plot like the pic below which the relating value of each curve is specified on several parts of the curve. Can anyone suggest a way? :)

As an example do it with the following function:


Can someone please let me know if there's a command which shows the name of the current (and running) worksheet? I would like it to be exported to an output file which is the easy part but I don't know how to automatically read it. Thank you very much.

i got kernel connection lost error when memory used reach 2.87GB

how to make it fully used 3.8GB ram, total 4GB ram

indexlistresult := [];
gaga := [seq(i, i=1..512];
indexlistresult := [op(indexlistresult), op(gaga)];
indexlistresult := [op(indexlistresult), op(gaga)];
indexlistresult := [op(indexlistresult), op(gaga)];
gg := permute(indexlistresult, 3);

I actually had the same problem on Maple 16. When i go to plot an equation (usually on implicit plots) it just repeats the equation in blue text rather than showing any sort of plot. Im sure i am just missing a simple option somewhere, but for the life of me I cant find it. Any and all help would be appreciated. 



I am trying to find the inverse of 8x8 generic symbolic matrix. Everytime I evaluate the program I get the following error:


Error, (in expand/bigprod) Maple was unable to allocate enough memory to complete this computation. Please see ?alloc


Can anyone guide me how to increase the memory allocation? And would that solve the problem for me?


Any help is appreciated.



Hi all.  I have researched into this problem.  But I could not find a solution to this.

Here is an example.

I have a set of independent variables, say there are 5 of them.  They are 1. Gender 2. Age group 3. Full or part time 4. First language.

I have a set of dependent variables.  Let us consider for an example 6 of them.  They are (i) Develops breast cancer (ii) Develops skin cancer (iii) Develops lung cancer (iv) develops prostate cancer (v) Lives till 50 (vi) Lives till 60 ...

How do I perform the following prediction:

(A) If a person is male and above 50, what are the chances that he is likely to develop prostate cancer?

(B) If a person is female and works part time, what are the chances that she is likely to develop breast cancer and lives till 60?

I need to develop a code and formula to do this?  Can someone please advise?

Many thanks.

Kind regards,


I have a question that says write a procedure that takes a random graph and three edges of that graph and returns true if those edges share a common vertex. So I was thinking of something along the lines of

proc55 := proc (G, {a, b}, {c, d})

if evalb({a, b} = {a, c} or {a, b} = {a, d} or {a, b} = {b, c} or {a, b} = {b, d}) then print(true)

else print(false)

end if;

end proc;


I guess my main question is how do I put edges in the parameters line? It will let me write proc (G, a, b, c, d) but not proc (G, {a, b}, {c, d}).

Is there just something I'm missing or am I approaching this in the wrong way?


I have a proc as follows:

for j from 1 to n do;
end do;
end proc;

I chose to use index variables. However when I try to apply a member of the output list as a function of the outermost limit, I do not get any output when I try to evaluate the function. I suspect maple is having trouble with the variables withing the integral. How can I make this work?

I'd like to have a function that I can evaluate:




1 2 3 4 5 6 7 Last Page 3 of 1057