## access to the indeterminate functions in dsolve or...

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I am trying to solve (numerically) the following system of differential equations using dsolve (Maple 9): DGLS:=seq(seq(diff(B[i,k](t),t)=add(add(W(j,l,i,k)*B[j,l](t)-W(i,k,j,l)*B[i,k](t),l=1..N),j=1..N),k=1..N),i=1..N); The problem is posed by the coefficients W(i,k,j,l). I want to make the W(i,j,k,l) dependent on the unknown functions B[i,k](t). For that purpose I wrote a Maple program W := proc(i::integer, k::integer, j::integer, l::integer) which calculates a "transition probability" Wtrans. If Wtrans does not depend on the B[j,l] (e.g. Wtrans:=1/N^2;), everything works nice. However, if I try to use the B[i,k] somehow (e.g. if NKrit_jl > B[j,l] then Wtrans := 0.5 fi;), then error messages from the procedure W result like "Error, invalid terms in product".

## Extracting an integer coefficient from a term...

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What is an efficient, robust, way to extract an integer coefficient from a single term? My first thought was using lcoeff, however, it doesn't work if the term contains constants (say Pi) or floats. Currently I'm using patmatch,
```icoeff := proc(t)
local k,x,kx;
return `if`(patmatch(t, k::'nonunit'(integer)*x::anything,kx)
,eval(k,kx)
,1);
end proc:
map(icoeff, [0, 1, -3.0, -3, -0.,  3.0*Pi, 4*Pi, -12/5*I]);
[0, 1, 1, -3, 1, 1, 4, 1]
```

## Can anyone tell me the difference of maple used in...

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One of my friends told me that Maple used in Linux(SUSE) is unstable,^_^，what he said may be wrong.I need more information about these,Anyone has even used maple in Linux(SUSE)? Can you tell me the difference of maple using in between Linux(SUSE) and Linux(RedHat)? I want to install maple V10 in SuperComputer Center for parallel computing.

## ¿Where do I get Maplet Builder for Maple 9.5?...

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Hi. I have done some reseach and I can't seem to find where to download the Maplet Builder for Maple 9.5. It was suppose I could download it from Maple Primes, but I don't find the appropriate link.

## How to analyze (local) convexity with Maple?...

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Hi dear Maple experts, I have a function f:= sin(x^2+y^2) and 1. I want to analize the convexity/concavity at a specific point (x,y) = (1/100,1/100) 2. It would be possible to check the convexity/concavity for all (relevant) points on the region x=-3..3, y=-3..3 ? (I suppose that is needed to discretize this region). 3. It would be possible to show a graphic (in R2) with colours (say, red for convex, blue for concave and yellow for neither concave nor convex)? Thanks a lot for reading this message, and thanks in advance. Jean Jacques

## Branches in numeric integration...

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A colleague is trying to evaluate some contour integrals numerically using evalf(Int(f,t=0..1)). Unfortunately f involves square and higher roots and Maple is getting an incorrect answer because it is not choosing the branch for these roots continuously through the range of integration. Apparantly Mathematica has an option in numerical integration which forces a continuous choice of branch for the integrand. Is there any reasonably simple way to achieve the same with Maple? Thanks.

## listplot3d problem...

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Hello, I am trying to do a 3d plot from 3 datapoints from a text file. I have the file DATA with 4000 data points in the following format: -1 -1 2 -1 -0.976522 2 -1 -0.952609 2 -1 -0.915507 2 ... Where columns respectivly are the x, y, and z values that I want plotted. I figured that this command should plot the points: listplot3d(readdata("DATA",3), axes=boxed, labels=[x, y, z]); I do get a graph here, but instead of plotting the points x, y, z, I get the x value correspoindng to the line number, a y value that seems to be the value of the y column + 2, and the actual z value that I want. So, my question is, how do I just plot the three values that I am inputting?

## use fortran77 in maple...

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Hi! I have a lot of programs made by fortran77, can i use this programs under maple10? thanks.

## scientific notation...

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Maple 10.(PC Version) In options or somewhere else... Is there a way to set the Scientific Notation threshold. Is there a way to determing what it is? Thanks, Dgiznya

## How to implicitplot/contourplot f(x,y,z) on R2 in ...

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Hi, I am very new in maple and I am learning the command plot/contourplot. Given, for example f(x,y,z) = x*y*z defined on x=0..1, y=0..1, z=0..1; I want 1. to implicitplot3d the function f for f(x,y,z)= 1, 1/2, 1/4, 1/8, 1/16, 1/32, ..., 1/2^10 2. to see the previous graphics only when (x>y ∧ y>z) 3. to CONTOURPLOT each "level" of f(x,y,z) obtained in 2 on the plane (x,y),(x,z) and (y,z). Thanks a lot in advance, Jacques.

## Solving nonlinear equations?...

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Hi, How to solve 12 nonlinear equations with 6 unknowns with Maple 10 or other software but analytic, not numeric? I was tried with solve(). After waiting 24h computation I was interrupt it. And I don't think that Maple will solve that problem. In begining CPU usage was 100% but latter was 0% and HD always read or write something without stoping.

## How to sum on j1, j2 and boolean expressions?...

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I want a function depending on n1 and n2, and a1 and a2, more or less in the following way: sum( sum( ((if ((j1*k1/n1 +j2*k2/n2+k2/n2 > 1/2) &and (j1*k1/n1 +j2*k2/n2 >1/2)) 1 else 0), j1=0..n1), j2=0..n2). How do I write in maple the previous expresion?. That is.. how may I write MYfunction( n1, n2) = sum( sum( BOOLEAN , j1=0..n1),j2=0..n2); where BOOLEAN stands for terms involving j1,j2,n1,n2 and other "constants"? Thanks in advance! Jacques

## F=ma solving...

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How does one get Maple to solve F=ma problems like r:=t->; When I try diffeq:=Diff(r,t\$2)+(r.r)^(-3/2)=0; I get > sol:=dsolve(diffeq,r(t)); Error, (in ODEtools/info) expected an ordinary differential equation. Received: 1/(r^2)^(3/2) = 0

## Problem with partial fraction expansion...

Asked by:
I'm posting this on behalf of a user (Peter) who is having problems attaching a file. Peter, I would prefer to try to resolve this issue here then through my e-mail. You will have more "eyes" on the problem on the site. My knowledge of German is limited to menus and street signs. But I am presuming your question is that Maple T.A. is marking the partial fraction expansion answer as incorrect when it is correct. We'll need to see the logic (code) behind the question to deduce where the true source of the problem is. Can you post a regular text post? If not, send me an e-mail. Thanks.

## Where is the problem?...

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Hi I work with Maple 9 and I came across to this problem. I don't know where the problem is. >restart: > simplify(convert(sin(1/2*Pi*(-I*x+5)),exp)); > simplify(convert(cosh(1/2*Pi*x),exp)); does it mean that: >sin(1/2*Pi*(-I*x+5))=cosh(1/2*Pi*x); for all x's? Now look at this paradox: >x:=100; > evalf(sin(1/2*Pi*(-I*x+5))); > evalf(cosh(1/2*Pi*x)); where is the problem? cheers Sayed
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