## Complex differential equations...

Hi, I am trying to solve a first order differential equation numerically using dsolve. The equation is of the form dx/dt = k1 x + k2 |x|^2 x where x(t) is a complex valued function and k1 and k2 are complex constants. I get the following warning/error from maple10 Warning, abs is not differentiable at non-real arguments For this equation dsolve only gives me the solution for relatively short times (t ~1 or 2) and I know there is a solution valid at large times >>1. Obviously I could cast this equation into a system of 2: one for the real part and the other for the imaginary part.

## Simultaneous Algebraic Equations...

Given N-1 independent (not necessarily linear) equations in N variables, how do I tell Maple to find solutions in terms of a specific variable? For example: with(RealDomain); eq1:=x-1=a*cos(theta); eq2:=x+1=a*sin(theta); I want to find a and theta in terms of x: a=sqrt(2*x^2+2), theta=arctan((x+1)/(x-1)) solve({eq1,eq2},[a,theta]) appears to give me solutions based on elimination of x.

## Hiding the axis' scale when plotting?...

Hello! Another newbie question. How do I prevent Maple from displaying the actual numbers on the x-axis and y-axis in a plot? I've looked around in Help, but couldn't find anything useful... Thanks for your interest! Carolus

## problem with Maple10...

Hi guies, my Maple is out of order because my "kernel connection is not available" and Maple is closed by "mserver.exe"; my firewalls are stopped when I open Maple. Before this problem Maple did'nt find the dll:"libgmp-3.dll".However I reinstalled Maple. What can I do? Thanks

## Plot a function against another function?...

I have two functions describing the physics of gamma radiation. I want to plot one function in terms of the other, i.e., set my x-axis to one function, and my y-axis to the other, to see there relation as there values increase. How do I do that? Thanks.

## Using fopen problem...

I would like to read a data file that is located in "My Documents" folder using the open command, but maple cannot find the file. The file name is data1.txt and I think the complete folder name is c:\Documents and Settings\dhalpern\My Documents I have tried INP := fopen("C:\Documents and Settings\dhalpern\My Documents\data1.txt",READ,TEXT); but I get the following error message. Error, (in fopen) file or directory does not exist I have checked that the file and directory DO exist. If I place the data file in c:\ then I don't have any problems but I would prefer to have my files in My Documents.

## Factoring equations...

Hello, A few minutes ago I uploaded of file 'georgeworksheet2.mw'. which contains a question which I have for this forum. I have tried to incorporate this file into my post by clicking on the blue type which says "Upload/Use File or Worksheet" but when I click on this nothing happens. I believe this link is supposed to take me to "http://mapleprimes.com/filemanager", but nothing happens. Perhaps this is a problem with the website which should be looked into. In the mean time, if anyone is able to get to 'georgeworksheet2.mw' and respond to the question I present in the worksheet I would be most grateful.

## Pi tickmarks on the x-axis

by: Maple
The question of how to scale the x-axis with intervals of Pi has been raised on a number of occasions. Inspired by a contribution from Will, I produced the procedure and examples shown in the worksheet attached below. Hopefully, Maple users will find it useful. J. Tarr View 724_Pi axes.mw on MapleNet or Download 724_Pi axes.mw
View file details

## Automated PDF file output in Maple?

by: Maple
Does anybody know why Maple's support of PDF is so poor? I posted a forum topic entitled "PDF support" in the past but didn't get any satisfactory answers. Suppose that I want to automatically generate a bunch of PDF files in Maple and manually saving each one as PDF isn't an option because it is too time consuming? Am I the only Maple user who has ever encountered this option? A search of the web seems to indicate that this is the case. I want to use Maple over Mathematica, but this is one issue that has prevented me from making the switch (permanently) so far. I am currently running Maple 10.04 for Mac on OS 10.4.8 on a G4.

## Request for the procedure of my series of calculations...

by: Maple
restart:with(LinearAlgebra): L:=407: > L2:=convert(L,binary): > N:=length(L2): > T:=2^N-L: > TB:=convert(T,binary): > k:=length(TB): > T2:=convert(T,base,2): > T2V:=Vector[row]([T2,0\$(N-k)]): > T2VC:=Vector[row]([1\$N]): > T2V1:=VectorScalarMultiply(T2V,-1): > T2VA1:=VectorAdd(T2VC,T2V1): > ADDT:=Vector[row]([1,T2VA1]): > B_N:=Array(Hessenberg[lower],1..N+1,1..N+1,(a,b)->1): > C:=convert(B_N, Matrix): > Permanent(C): > delB:=DeleteRow(C,N+1..N+1): > B(L):=Matrix(N+1,N+1,[[delB],[ADDT]]): > Permanent(B(L));

## Maple Error in 3d plotting

by: Maple
Hi all, I am Using Maple 10. i am getting a frequent bug When i plot a 3d graph. Description: In a 3d plot, if i rightclick after rotating the graph, maple exits automatically. can somebody please tell me what's the problem? Thank you Divahar.J Indian Institute of Science, Bangalore, India.

## Integral of 1/cosh x?...

I've been struggling with the integral 1/(1+x^2)^2 ... i managed to use the substitution x=sinh(x) to get it into the form 1/cosh x but now im stuck! im not sure if the initial substitution was even right ... any help much appreciated! ps i know this is not strictly a 'how to' maple qu ut i thought youd all be the type of people that could help me!

## How to multiply functions f(x) and g(x)...

View file details What's the correct Maple command to graph of the product of f(x) and g(x) ? How to graph conic sections in Maple? Lastly, How to evaluate and graph f(x) compose with g(x)?

## Automatically generate a function of an array or v...

As an engineer I typically do a lot of work with matrices and oftentimes symbolic matrices. I might generate a symbolic matrix and perform some computations that creates a function of the symbolic elements of the matrix. I now want to turn those symbolic expressions into a procedure that is a function of the matrix array input. How can this be done? There does not appear to be any simple solution. This task is so obvious and so common that I'm shocked there is no simple answer. Here is a trivial example The symbolic matrix with( LinearAlgebra) : U := Matrix(2,2, symbol=u) ;

## Q: using sscanf...

```I do not understand how to use this command (on strings), I want to convert