Hi, Solving a non linear eq. system I got the solution posted below. Here I only show one solution for a certain value of "a2", but in fact I got n rigs as n values of "a2" I am interested.

The Question is:How can I isolate a value from this solution,for instance to create a vector with the several "P" results for each solution given.Thanks,JPA

With a Mac using Firefox you would hold command + alt and left or right arrows to change between tabs.

 

How would you do this in Maple? Does such a feature exist?

Hello all,

I'm running into a bit of a problem finding an efficient way of forming the expansion coefficient for an eigenfunction expansion. The way I currently have it coded works, and it doesn't take terribly long (about 30 seconds or so). However, I have to run a lot of different evaluations, so all that time begins to add up. In addition, the memory usage balloons until I am pretty much frozen and unable to complete the calculations.

So, here's the block of code that's causing me problems:

for p to P do

for q to Q do

Hi, all, I have a list of polynomials and then I want to get polynomials which include given variables. How can I do this? For example, I have a list: L:=[a+b+c,x+ab+d^3,y+c]; and I am only interested in polynomials which include varaibles "a", "b", "c", which is "a+b+c". Which command can implement this? thanks Gepo

Hi, I'm working on the Smoluchowski equation (essentially the diffusion eqn with an extra derivative) diff(u(x,t),t)=k*diff(u(x,t),x)+D*diff(u(x,t),x,x) k is piecewise so the function has to be solved numerically, the boundary values are specified u(0,t)=u(1,t)=0 but i need the derivative at the boundaries D[1](0,t) and D[1](1,t). It seems to be simple to evaluate a numeric derivative of an ODE but I can't see how to do it for a PDE. Any help welcome, even some sort of brute force method if necessary. Thanks, Ryan

How do i convert a curve into its data points i.e. how can  i get the points from a curve.

Thanks

Hello,

I have a system of polynomials that I need to calculate its primedecomposition.

It has been trying for several hours but it could not give me result.

Even I tried to have Grobner basis and I could not.

Could you please let me know what should I do for that?

View 7845_Q1.mw on MapleNet or Download 7845_Q1.mw
View file details

 

I dont understand what's the 'label' thing in the answer here.

 

Thanks.

 

casper

Suppose I want a random sample of 500 numbers

RandomSample(Normal(0,1)),500);

Good, now if I am understanding properly [0,1) means positive values with a mean of 0 and standard deviation of 1.  However in Maple RandomSample(Normal[0,1)),500); is not allowed due to bracket mismatching. 

how do I get the RandomSample domain [0,1)?

Hi all I've a program running that has been stopped with the error Execution stopped: Stack limit reached. at that time the program was using memory used=480073.6MB, alloc=594.8MB, time=16330.02 The host computer has 16 CPUs and 50Gb of Ram, so I don't think the problem is the memory... Any hints? Thanks Salvo ps: I've found an old discussion about this problem, but it was very old (2005, M9) so I've thought I could open a this one.

I am trying to solve a set of 4 coupled ordinary differential equations, starting from certain set of initial conditions for certain parameter values.  i have to evolve the system for a very long time (higher number of iterates are needed).

For a certain set of initial conditions the following error occurs

"Error, (in sol12) cannot evaluate the solution further right of 2939.9221, probably a singularity"

what could be the possible way to get rid of this error.......

I'm new to programming.

I don't understand what I'm doing wrong in this

If anyone could help me with this, I'd very much appreciate it.

See the attached picture called "equation". That is the differential equation I'm trying to solve. The graph (for m=1) should like as it does in the other attached picture called "graph".

I tried this

----------------------

with(DETools):
m := 1;

de := diff(y(x), x, x, x)+((m+1)*(1/2))*y(x)*(diff(y(x), x, x))+m*(1-(diff(y(x), x))^2) = 0;

DEplot(de, y(x), x = 0 .. 8, [[y(0) = 0, (D(y))(0) = 0, (D(y))(infinity) = 1]], y = 0 .. 1);

---------------

But goes this error message

Error, (in DEtools/DEplot/CheckInitial) initial point in all initial conditions must be the same

I don't know how to get around this because my initial conditions are what they are, I can't change them.

Does anyone know of a way to fix this or know of a better way? The reason I need this is because I need to get the graph for m=0.77, which isn't in those photos.

 Any help is appreciated.

 

 

Im  writing a loop which starts by solving a circle equation,  how do i instruct maple to follow another another set of instruction if no real roots are found?

im looking to do something like this

(x1a, x1b) := fsolve((x-h)^2+(eq2-k)^2-r^2)

if real roots are found, do this

else, do something else

end if

I hope im clear enough on what im asking. If not, please let me know.

thanks

Lovinash

Hello

I have a matrix, let's call it A. I want to define a new matrix by taking every n-th row in the A matrix. How do i do that?

For example,

A= | 2 3 5 |
     | 9 2 1 |
     | 5 1 2 |
     | 1 8 9 |

 

the B, if n=2, is equal to

| 2 3 5 |
| 5 1 2 |