## How do I take only positive root from solve(polyno...

I have written a loop that should create an array, but because I am solving a polynomial both solutions are given in the array. Is there a way to just select out the positive root so that I can plot with this array later? Any help would be greatly appreciated. Nick

## Differential equation with least square method...

Hello, I am working on a problem that I cannot solve for several days. Any help is welcomed :) I have a differential equation y''(x) = a * y'(x) + b * y(x) + c I have two vectors X = (x1, ..., xn) and Z = (z1, ..., zn) y(x1) = z1 y(xm)=zm I have to solve the problem by determining the 'a', 'b' and 'c' by using least square method. I am trying to use dsolve to get a solution of the differential equation and then the Optimization package to use the least square method, but I cannot get it right. Thank you very much for any help.

## Maple 11 features...

How can I create a 3D images in Maple 11 without entering any expression?Is it by using the new drawing tools?

## different parsers

by: Maple

I was mulling over an example that behaved differently when cut and pasted in a Document (2dmath input) and a Worksheet (1dmath maple input). The example was this,

M := Matrix([a]);
N := Matrix([b]);
(M.N)[1,1];
(M.N+N)[1, 1];

The last line of that, in Maple 11.00, produces the product of the list [1,1] and the addition M.N+N, instead of indexing into that sum's Matrix result as it does with 1dmath input.

Is that a bug? Clearly there are...

## source code...

hi... can any one give me general source code for random generator? i need to use the source code for my project... thank you..

## Producing Data from 2D Plot Structure...

Is it possible to produce a file of something like tab delineated data via a 2D plot object? Basically all I want to do is create a data file using the points stored in the plot structure for use in a METAPOST file, and I haven't been able to come up with anything. Any help would be greatly appreciated. Thanks a lot. Keenan

I'm working on a problem for class that requires me to use dsolve but, I'm getting a generic error when I try to use dsolve the exact same way they use it in the example. my code is: A:=matrix([[-1,0],[1,-2]]); B:=matrix(2,1,[1,-1]); ics:=x(0)=matrix(2,1,[1,0]); equ:=diff(x(t),t)=A*x(t)+B; dsolve({equ,ics},{x(t)}); Error, (in solve) invalid arguments I don't know what's wrong with this since its almost exactly like the example they give for dsolve.

## My class needs help...

My class was given this question as a final homework but we can't figure out how to solve it. We have talked to the professor on multiple occasions but he will not provide any help. If anyone knows how to solve this using maple, please help. The question is below... solve x(t) = Ax(t)+B where B=[1 -1] A=[-1 0 1 2] and x(0) = (1 0) Sorry for the matrix formatting but, I don't know how to use the math equations here.

## How to install fourier series part 4...

I downloaded the files for this app but I did not see any instructions on installing this. Can anyone help me install this library? Thanks

## Greedy Heuristic in Maple...

Maple Professionals: I wish to prgramm a greedy heuristic in maple and would be more than grateful, if someone could help me, since I am no expert in programming. The problem is a simple stocking problem. There are two parts I wish to stock in my warehouse. I know their demand, delivery time and item cost. From the demand and the delivery time I can calculate the expected backorders given a specified number of units in stock based on a poisson distribution. In the greedy heuristic step by step I increase the stock of all items by 1 and then calculate the reduction in expected backorders divided by the item cost (some kind of "bang per buck"). I then compare the reduction over all items and increase the stock by one for the item with the highest reduction.

## Maple cuts my output......

Hi ! Sorry for my english... I'm finding roots of polynoms like X²+ aX + b, a and b can be very complicated, with a lot of square roots inside. When maple gimme the roots, or when i assign some variables, it try to simplifie the output, creating "subsections" named %1 or %2 etc... For example : Or How can i get the output without theses "simplifications" ?

I recently purchased Maple 10. In the user manual is described that 95% of Maple is open-coded, but in fact only eval(packagename[command]) really show the program in Maple for related toolpackages.It is far away from 95%! Where am I wrong?