So here is the issue: I have a 50 by 50 tridiagonal matrix. The entries in the first row, first column are -i*x and the last row last column is -i*x; these are along the main diagonal, where i is complex and x is a variable. Everything in between these two entries is 0. Above and below the main diagonal the entries are -1. My issue is that I have to find a conditon on x that makes the eigenvalues real. I am completely new to maple and have no programming experience.. Can someone show me how to this?

Using Maple 18, I solved for minimum and maximum price. Instead of using fsolve I wanna use procedure programming structure in order to get the same results. How can I do it?

min_sol := fsolve([bc_cond, slope_cond, x[G, 1] = w[aggr, 1]], {p = 0 .. 1, x[G, 1] = 0 .. w[aggr, 1], x[G, 2] = 0 .. w[aggr, 2]}); p_min := subs(min_sol, p); max_sol := fsolve([bc_cond, slope_cond, x[G, 2] = w[aggr, 2]], {p = 0 .. 1, x[G, 1] = 0 .. w[aggr, 1], x[G, 2] = 0 .. w[aggr, 2]}); p_max := subs(max_sol, p);
{p = 0.3857139820, x[G, 1] = 127.8000000, x[G, 2] = 38.99045418}
0.3857139820
{p = 0.8841007104, x[G, 1] = 44.30160890, x[G, 2] = 164.2000000}
0.8841007104

Hi,

I am trying to realize the following calculation in Maple.

$
  \left[\sum_{i=0}^n y_i(x) \partial_x^i , \sum_{j=0}^m z_j(x) \partial_x^j \right]  \\
=   \sum_{i=0}^n \sum_{j=0}^m \sum_{l=0}^i  \binom il y_i(x) \left( \partial_x^{i-l} z_j(x)\right) \partial_x^{l+j} \\
- \sum_{j=0}^m \sum_{i=0}^n \sum_{l=0}^j  \binom jl z_j(x) \left( \partial_x^{j-l} z_i(x)\right) \partial_x^{l+i} \ .

$

Is there a way to make maple understand d/dx as a differential opperator and calculate with it? When i for example try to calculate diff(d/dx, x) it should give me d^2/dx^2 as a result. Unfortunately i don't know how to realize this.

Basic problem is i don't know how to realize operator expressions in maple like for example:

f(x) d/dx      ( f(x) is a smooth function of x here )

where when applied to a function h(x) it should result in f(x) d/dx h(x) .

Is that possible?

Thank you very much in advance.

I am trying to expand out the terms  of equation 13.  The expand command causes the lhs to be zero?

Download Question_R12.mw

I want to know with what x,y, z,  function f is minimum, whereas function g is constant.

regards

Hi

I want to know with what x/y, z,  function f is minimum, whereas function g is constant.

regards

Hello every one,

Is any one knows how to solve the following inequality with assumptions that all parameters are real positive and k<1 and delta > c*alpha

(1/2)*((alpha*k^2-3*alpha*k-2*beta)*sqrt(delta^2*(k-1)*(k-2)*(c*alpha-delta)^2)-k*delta*(alpha*k^2-3*alpha*k+2*alpha-2*beta)*(c*alpha-delta))/(delta^2*(alpha*k^2-3*alpha*k-2*beta))<0

I tried the following code but it  dosn't make sense:

u:=(1/2)*((alpha*k^2-3*alpha*k-2*beta)*sqrt(delta^2*(k-1)*(k-2)*(c*alpha-delta)^2)-k*delta*(alpha*k^2-3*alpha*k+2*alpha-2*beta)*(c*alpha-delta))/(delta^2*(alpha*k^2-3*alpha*k-2*beta))

solve({u < 0,alpha > 0, beta > 0, c > 0, delta > 0, delta > c*alpha, k > 0, k < 1, })

In fact I want to know under which circumastances the above inequality is negative.

THX

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Is there a command in maple that shows which files were read during start up? I am confused as to which maple init file is being read on my PC.  From http://www.maplesoft.com/support/help/Maple/view.aspx?path=worksheet/reference/initialization

it says

"Under Windows, the initialization file is called maple.ini.
If <Maple>\lib\maple.ini exists, it is loaded first (where <Maple> is your Maple installation directory). With a  network installation of Maple, the commands in this initialization file will be executed by all users on the network.
To execute a user's personal set of commands, only the first initialization file in one of the following paths will be loaded.
1) The binary directory of your current working directory (for example, "c:\Program_Files\Maple\bin.win\maple.ini")
2) The <Maple>\Users directory (for example, "c:\Program_Files\Maple\Users\maple.ini")
3) The user's personal profile directory (multiuser only) (for example, "c:\Documents_and_Settings\userid\maple.ini")
      
Maple reads and executes the network initialization file before the personal initialization file."

How do I find out, from inside Maple, which file(s) were read? Or make maple shows a trace of the loading process to see what files ini files it is reading?

Maple 18.2 on windows. btw, the above help page seems old. I am on windows 7, and I do not have "c:\Program_Files\Maple\" folder. And do not have "c:\Documents_and_Settings" folder. So the above help is not very useful. May be it was written during windows 95 times?

Hi all,

I have some "boolean variable" constraint equation like this:

a1*x1+a2*x2+...+an*xn>=b1*y1+b2*y2+...+bn*yn

where a1,a2,...,an and b1, b2, ..., bn are 1 or -1

These equations will be used in LPSolve or the other command to find a group of parameters which can fit them.

Now I used for-loop to deal with this kind of question, for example:

But there are more than 10 boolean variables in my case and It's very inefficient. On the other hand, using for-loop to determine the equation we solve in the command will lead to great confusion.

I think there should be some ways able to solve this kind of "boolean variables" question in Maple, such as, through assume command to define the type of "boolean variable".

But I have no idea how to do it.

I have the following construct:
for i from 1 to 10 do
cubeprod:=i^3;
if irem(cubeprod,3)=0  and if(modp(cubeprod,2)<>0 then
cubesum(cubeprod);// I need both if statements to be true in order to invoke cubesum(). I've noticed that using an and between both if statements is incorrect but :

for i from 1 to 10 do
cubeprod:=i^3;
if irem(cubeprod,3)=0 then 
 if modp(cubeprod,2)<>0 then cubesum(cubeprod) fi;
end if;
end do;

gives me an error as well. What is the right syntax to achieve this?

I have the following procedure to do the above. It works but it returns [9,10],[10,9],[12,1] for n=1729(for example). How do I modify this to 

a) to count 9,10 and 10,9 as the same and hence only show one of them

b) get 1,12 to show as a solution?

cubesum:=proc(n::nonnegint)
global listcub:=table();
local k:=0, x:=iroot(iquo(n,3),3),y:=x,x3:=x^3,y3:=y^3;
if 3*x3 <> n then x=x+1; x3:=x^3;y:=x;y3:=x3 end if;
while x3<=n do
y:=iroot(n-x3,3); y3:=y^3;
if(x3+y3 = n) then k:=k+1; listcub[k]:=[x,y]end if;
x:=x+1; x3:=x^3;
end do;
convert(listcub,list);
end proc:

Hi
I have my question makes any sense. I am from Denmark and not used to write math in english.

I have an characteristic matrix with an variable λ that takes on differen values.

How do I write λ in the matrix so Maple knows that when I call out a row with the variable λ in it and asssign

λ to a specific value, Maple changes λ to the specific value.

Example (I was thinking something like this):

A:=Matrix(2,2,[(1-λ_i),2,3,(4-λ_i)])

λ_1:=2

λ_2:=4

A[1],λ_1               (1-2) 2

A[1],λ_2               (1-4) 2

A[2],λ_1               3 (4-2)

A[2],λ_2               3 (4-4)

Hi, I am an student and I am currently working on a system that sketches the relation of predator and prey of yellowstone's gray wolf and elk. I tried using the Lotka-Volterra model, but I wanted to add more parameters and add a carrying capacity for the system. Unfortunatley I cannot find a way to edit the Lotka model to my needs, and because I am new i do not know how to create my own model. This is the two equations I want to use: (D(x))(t) = alpha*x(t)-ax^2/k-b*x(t)*y(t)-gx(t), (D(y))(t) = -beta*y(t)+c*x(t)*y(t)-gy(t)

were k is carrying capacity.

Basically what I am asking is that if someone can help make the system workable on Maple and some steps of how to do it. 

What I tried is at

http://apfp.sourceforge.net/maple_interval_arith.pdf

I would like to be able to do comparisons of intervals.

At least take min or max - I thought I saw that on help pages but didn't get it to work.

Would also like to use with complex numbers - tried evalrC - but did not do what I expected.