## Need some help in Non-Linear differntial equations...

Hi.... I am facing some problem in solving a Non-linear differential equation using Maple 11. So many times maple 11 doesnot execute the command and comes out. Sometimes, it just says evaluating for a long time and nothing happens. I would be very happy if you can give me the solution of the same with an example. Regards Sripad

## Storing and using imtermediate results...

With my calculator, I can store and then use intermediate results in the following way. Lets say the result of an equation is 1.234 and I will be using those results in other calculations. If I enter 1.234->a where the arrow represents the store key, the value of 1.234 in now stored as "a" and I can use "a" in further calculations, for example 2a followed by enter will return 2.468. How do I do the same type of thing with maple? (Thank you)

## Expand and Collect commands...

With my graphing calculator (TI-voyage200) I can expand and collect multiple angles per the familiar trig foumulas. For example with my calculator I can enter tExpand(sin(2*x)) and 2*sin(x)*cos(x) is returned. To do the reverse I simply enter tCollect(2*sin(x)*cos(x)) and sin(2*x) is returned by my calculator. With Maple, I find that I can use expand(sin(2*x)) to get 2*sin(x)*cos(x) but collect(2*sin(x)*cos(x)) doesn't perform the reverse the operaton. How can I do the reverse operation, for instance by entering what command along with 2*sin(x)*cos(x) and have sin(2*x) returned???

## Matrix from the section of rows and columns of ano...

Hello everyone,I'd like to ask a question. Using the "LinearAlgebra" package, is there a (automatic) way to create a matrix from the section of rows and columns of another matrix already in use? That is, we have A:= a 5X4 matrix and we want to create, let's say a 3X2 matrix from the elements of A that belong in the section of rows 2,4 and 5 and columns 2 and 4 of A. Ok, we can write a small routine, but I would like to know if there's a fast and straight way to do that. Thanks in advance!

## My first algorithm and my first time programming.....

Maple Professionals: This is my first time programming. I wish to compute a marginal analysis algorithm, where I basically want to find the best bang per buck in each step. I increase the variable s[i] one after another by 1 and look at the change in the perforance realtive to the cost. Then I wish to increase that s[i] by 1 for which I could see the largest increase in performance relative to cost. In the end I wish to stop when the performance measure DFR is larger than 85%. However at the moment I especially face the difficulty to raise that s[i] by one, which reached the largest relative performance increase. At the moment I got this far and would be more than grateful for any help from your side:

## How do i have just 1 instance of Maple?...

Hello How can i have just 1 instance of Maple opened. Because when i open an worksheet (with the .mw extension), another copy of the Maple main program opens which is RAM consuming. THX

## Whats with these symbols?...

In the Maple 11 user manual, at the beginning, on page 1 is an integral of sin(1/x)dx from zero to pi. The solution is given as an expression including -Ci(1/Pi). No definition or explanation is given for Ci. So my obvious question is what in the world is this Ci? I suspect it is a constant but if that is true, why doesn't the program present it's value? Then on page 20 is another integral where the answer is given as 1/2 erf(1)sqrt(pi). Here again, there is no explanation of what in the world erf(1) means, so what in the world is erf(1)?

## Importing .csv or .txt. file does not work.......

Maple Professionals: I wish to import a file with float type values which is 338*16 big. I saved it in Excel as a .csv type file. Using the Import Assistant works. However I don´t want to use the assisstant everya time I run my calculations. Thus I tried to use the commands readdata(), ImportMatrix(). Hoever non of those do like me :-(. I am really frustrated. I attempted the following commands, having already converted the csv into a txt: > lambda:=ImportMatrix("D:\01_1_CSML DATA\Prognose & Bestände\04_2.txt",datatype=anything); Error, (in ImportMatrix) file or directory does not exist

## Getting started - top commands...

In reading through the Maple 11 "Getting Started Guide," on page 81 is paragraph 4.2, which is titled "Top Commands," the booklet lists and describes a number of commands such as plot, solve, fsolve, eval, etc., with out any comment. What is the significance of these commands among the many, and what is meant by "top" commands. Is there a hierarchy of commands? Or do they mean these are the most used or what? I don't understand what I am missing here or why this list of commands in included. Again, there is no discussion, just the table of commands.

## imaginary roots of univariate polynomials

by: Maple
I thought that I would try to put some tips down in writing here, over time. I'll start off with something very easy.

Some users may have noticed that there is a new, faster routine in Maple 11 for finding purely real roots of polynomials, see ?RootFinding,Isolate . This gets used by fsolve, when only the real roots of a univariate polynomial are requested. Such a request occurs when the 'complex' option to fsolve is not supplied. This new solver is much faster than what was used by default in Maple 10.

## skip to top of page to print new iterated value in...

Hello, I have a do-loop printing "n" occurences of a certain calculation+plot. Each one has a different length. It would be neater to skip to the top of new page each time. How do I give the instruction: "move to the top of the next blank page"? Thanks. Philippe Baille

## named type...

Hello everybody. This is my first post. I'm currently using Maple 10 for a project in my school and i need to create types. I'm improving an "automatism library" called AutoSLI and for example i have to create a "transfert function" type. I want to use the type in functions like that : "zeros(Transfertfunction :: f) I use a "Record" structure inside a function. I make some tests to see if the parameters entered are correct then i create the object but it don't works when i use 'type/transfertFunction'. It creates the object when i take back the name of the type. Maybe the choice to put the creation in a function is not good.