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I have the following characteristic equation by use of maple. How do I find a condition on x, that will return real eigenvalues and complex eigenvalues?




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?

I've got the following matrix :

A:=[<a,a-1,-b>|<a-1,a,-b>,<b,b,2a-1>] where <> are the column elements of A, a is  a real number defined on [0,1] and b^2=2a(1-a) 

a) to show A is an orthogonal matrix, I understand that I need A.Transpose(A)=Identity(3*3) but is there a way in which I can let a take a random real numbered value between 0 and 1? The rand() only returns an integer within a range. Directly multiplying A and Transpose(A) will return an expression in a, so what's the right approach?

b) from a) we can infer that A is a matrix that describes a rotation in e1,e2,e3 where these are the standard bases vectors in R3. How can I determine the rotation axis? The hint I've been given says I need to consider the Eigenvalues and eigen vectors but I don't quite understand how.

Hi there,
I have a set of differential equations whose solution, Jacobian matrix and its eigenvalues, direction field, phase portrait and nullclines, need to be computed.

Each of the equations has a varying parameter.

I know how to get the above for a single parameter value, but when I set a range of values for the parameters, Maple is not able to handle all cases as I would expect: solving the differential equation system:

eq1 := x*(1.6*(1-(1/100)*x)-phi*y)
eq2 := (x/(15+x)-0.3e-1*x-.4)*y+.6+theta
desys := [eq1, eq2];
vars := [x, y];
steadyStates := map2(eval, vars, [solve(desys)])

already yields an error:
Error, (in unknown) invalid input: Utilities:-SetEquations expects its 2nd argument, equations, to be of type set({boolean, algebraic, relation}), but received {-600*y+(Array(1..2, {(1) = 8400, (2) = 15900})), Array(1..5, {(1) = 0, (2) = 0, (3) = 0, (4) = 0, (5) = 0})}

The equations are the following:
de1 := diff(x(t), t) = x(t)*(1.6*(1-(1/100)*x(t))-phi*y(t));
de2 := diff(y(t), t) = (x(t)/(15+x(t))-0.3e-1*x(t)-.4)*y(t)+.6+theta

the parameters being:
phi:=[0 0.5 1 1.5 2]
theta:=[5. 10.]

How can I handle the situation so that Maple computes each of the above for each combination of the parameters?

I would like to avoid using two for loops and having to store all results in increasingly bigger and complicated arrays.

The worksheet at issue is this:


Hi there,

I would like to have the Jacobian matrix of an ODE system evaluated, and their eigenvalues computed, at the steady states of the system.

I know how to get the Jacobian matrix evaluated and the eigenvalues computed on an individual basis, setting manually each steady state as the argument of the matrix.

However, I would like to have it in a loop, so that the loop manages all steady states, that is:

steadyStates:= solve(mySystem); # would yield a set of pairs/lists

for each steadyState

m:=Jacobian(steadyStateN); # evaluate the Jacobian matrix

ev:= eigenvals(m); # compute the eigenvalues and save them to another variable/array and print them

end for:

First, I am not to find a way to loop over my steadyStates.

Attached is an example where the Jacobian matrix and eigenvalues are computed individually, where the steady states have been hard-coded once they have been computed:


Any ideas on how to do this?





I am trying to simplify the eigenvalues of a 2x2 matrix [[a,b],[c,d]] subject to the condition a,b,c, and d are integers such that a+b = c+d. Why do the following commands not achieve this?



Eigenvalues(A) assuming a::integer,b::integer,c::integer,d::integer,a+b=d+c

How might I achieve what I need?

Hello,In short: I try to get the eigenvalues of a 16x16 complex matrix with one variable B__z. I know, the vales are very small (~10^-24), so I multiply with 10^24 and collect B__z. Now, when I use Eigenvalues(H) [H is the matrix] the result is just wrong:

(same with original values) - compared to Mathematica which solves and plots in about 1 sec:

Where is the problem? What should I do? Any suggestions?


first of all, this is my very fist question in this forum, so please excuse some formal mistakes I may make...

Using Maple 18.01 on Windows 7 64bit

To the topic: I want to calculate the eigenvalues of a complex matrix like this (just as an example):

M := Matrix(2, 2, {(1, 1) = a+2.5*I, (1, 2) = 1-I*a, (2, 1) = 4, (2, 2) = a})

When I try to calculate


I get

Error, (in LinearAlgebra:-Eigenvalues) expecting either Matrices of rationals, rational functions, radical functions, algebraic numbers, or algebraic functions, or Matrices of complex(numeric) values

Strange, because if I replace the "2.5" with just "2", so an integer instead of a float, I get results:

I don't understand this strange behavior, since Mathematica i.e. calculates everything just fine...:

Thanks in advance for any suggestions.

Hi there

I have have a 18*18 matrix which almost each of its element are in symbolic form. Now I need to have all of its eigenvectors. Unfortunately when I use the "Eigenvalues()" function in maple i got nothing. In fact I got the error which comes below.

Error, (in content/polynom) general case of floats not handled

I need to know if there's a solution to eliminate the error? If not, what can I do to determine the eigenvectors and eigenvalues in symbolic form?

I'll be appreciated your help

Hello, everyone. I have some problem with multithreaded calculation. I just need calculate eigenvalues of matrix m at various parameters (and then export to a file) using advantages of the parallelizing. The following code works but in serial way


restart: with(LinearAlgebra):

m:=ImportMatrix(cat(currentdir(),"m.txt")): # here is matrix m.txt




local u,i,j,nmc:



for i from 2 to op([1,1],u) do


end do:

for i from 1 to op([1,1],u) do

nmc:=sort(Eigenvalues(m*u[i,1], output='list')):

for j from 2 to op([1,2],u) do


end do:

writedata[APPEND](cat(currentdir(),"u_",convert(k2,string),".txt"), [convert(Re(u[i]),list)]):


end do:

return finished:

end proc:



Start(ArrayTools[Concatenate], 2, Task=[prc,1,20], Task=[prc,20+step,40]);



The Start(ArrayTools[Concatenate], 2, Task=[prc,1,20], Task=[prc,20+step,40]) function makes two tasks of calculation at the parameter ranges of 1-20 and 21-40. But in this case Start spends twice more time than simply prc(20+step,40). How to realize a multithreaded calculation?

By the way I don't need to use a Concatenate function in Start but without any procedure Start doesn't work.

Aslam-u-Alikum... How are you? Hope you will be fine. I want to determine the eigenvalues of differential equation in Maple kindly help me... Problem.docx

Good day,

I try finding the eigen values of a 6 x 6 matrix with symbolic term but recieve the following error:

Error, (in expand/bigprod) Maple was unable to allocate enough memory to complete this computation.  Please see ?alloc

Please what do I do.


Hello guys , i have a matrix that i want to find its eigenvalues , i have its answer but maple calculations didnt give its anwer.


m and q can bu any number

maple calculation :




thank you guys


     I have a a matrix with one symbol and all others are numbers. I got this from doing 

   M := (1-x)*N + x*A :

 So my parameter is x, and N, A are numeric (real, symmetric) matricies. I want to plot the eigenvalues as x=0..1, but for a large matrix, say 25x25. Eigenvalues(M) only returns 17 eigenvalues, and more so, it doesnt keep them in the same order when plotting!

My issue is when Maple computes the...

how to find eigen value this 4x4 matrix:

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