Eigenvalue Definition and 382 Threads

  1. J

    Eigenvalue Theorem: Proof of Det(A - λI_n)=0

    Theorem: Let A be in M_n_x_n(F). Then a scalar \lambda is an eigenvalue of A if and only if det(A - \lambda I_n) = 0. Proof: A scalar lambda is an eigenvalue of A if and only if there exists a nonzero vector v in F^n such that lambda*v, that is (A - \lambda I_n)(v) = 0. By theorem 2.5, this...
  2. D

    Definition of a Differential Eigenvalue Problem?

    Homework Statement I would like to know what the definition of a Differential Eigenvalue Problem is please? I am a maths undergraduate. Homework Equations \lambda y = L y, where \lambda is eigenvalue, L is a linear operator. The Attempt at a Solution I have searched via google...
  3. S

    Is x in the nullspace of A an eigenvector of A?

    Let x not equal to zero be a vector in the nullspace of A. Then x is an eigenvector of A. I'm not sure how to start this proof
  4. S

    Proving Eigenvalues: A Unit Vector Approach for (A - λI)x = b

    Homework Statement Let x be a unit vector. Namely x(Transpose)*x = 1. If (A − Let x be a unit vector. If (A − λI)x = b, then λ is an eigenvalue of A − bx(transpose). The Attempt at a Solution I have no idea where to start this proof.
  5. S

    Proof of Eigenvalue of A^2 When λ is Eigenvalue of A

    Homework Statement Let λ be an eigenvalue of A. Then λ^2 is an eigenvalue of A^2 The Attempt at a Solution I know I have to start by using the fact that λ is an e.v of A then set up an equation relating the eigenvalues and vectors to A which is: Ax=λx. And I understand that the...
  6. B

    Linear Algebra - Diagonalizable and Eigenvalue Proof

    Homework Statement "Let A be a diagonalizable n by n matrix. Show that if the multiplicity of an eigenvalue lambda is n, then A = lambda i" Homework Equations The Attempt at a Solution I had no idea where to start.
  7. S

    Can Eigenvalues Be Shifted by a Scalar?

    Homework Statement Let λ be an eigenvalue of A. Then λ+σ is an eigenvalue of A+σI Homework Equations The Attempt at a Solution I'm guessing I need to use the fact that λ is an e.v of A to start with. But then when I add σ to both sides somehow I feel like I'm begging the question..
  8. S

    Proof: 3λ is an Eigenvalue of 3A

    Homework Statement If λ is and eigenvalue of the the matrix A then 3λ is an eigenvalue of 3A Homework Equations The Attempt at a Solution . . . λ is an e.v of A Therefore, ∃ x not equal to 0 s.t Ax=λx Then, 3Ax=3λx which can written as 3(Ax)=3(λx)=λ(3x) and 3x does not...
  9. T

    Finding a Non-Diagonalizable 3x3 Matrix with 2 as its Only Eigenvalue

    Homework Statement Find a 3*3 matrix A which is not diagonalizable and such that 2 is the only eigenvalue of A Homework Equations The Attempt at a Solution since λ=2,and it is a 3*3 matrix i get the det(λI-A)=(λ-2)^3=0 then λ^3-6λ^2+12λ-8=0 now i use...
  10. E

    A question about solving the energy eigenvalue of a given Hamiltonian operator

    The problem is A particle of mass m and electric charges q can move only in one dimension and is subject to a harmonic force and a homogeneous electrostatic field. The Hamiltonian operator for the system is H= p2/2m +mw2/2*x2 - qεx a. solve the energy eigenvalue problem b. if the...
  11. S

    What's the physical meaning of an eigenvalue?

    Homework Statement This isn't a homework problem, just something I've been trying to conceptualize for a while. Can anyone exemplify with a physical analog the concept of eigenstates? For example, I know that eigenvalues of variables with continuous spectra do not exist in the physical...
  12. J

    Eigenvalue Problem in Uniformly Acceleration Motion

    Homework Statement In Uniform Acceleration Motion, the force F is constant. then potential V(x)=Fx, and Hamiltonian H=(p^2/2m)-Fx The problem is to solve the eigenvalue problem Hpsi(x)=Epsi(x) Homework Equations F=constant V(x)=Fx H=(p^2/2m)-Fx The Attempt at a Solution I have...
  13. F

    Guess Eigenvalue of 2x2 Matrix with Constant k Sum

    Homework Statement Let A be a 2x2 matrix for which there is a constant k such that the sum of the entries in each row and each column is k. Which of the following must be an eigenvector of A? a. [1,0] b. [0,1] c. [1,1] (The answer can be any or all of these) The Attempt at a Solution I...
  14. D

    Finding eigenvector from eigenvalue

    Homework Statement For the matrix A = -1, 5 -2, -3 I found the eigenvalues to be -2 + 3i and -2 - 3i. Now I need some help to find the eigenvectors corresponding to each. Homework Equations The Attempt at a Solution For r = -2 + 3i, I plugged that into the (A - Ir) matrix...
  15. G

    Nilpotency of Matrix with one eigenvalue

    Hello everybody, I have a question for which I cannot find the answer around, any help would be really appreciated. Suppose we have a matrix A of a linear transformation of a vector space, with only one eigenvalue, say 's'. My question is: Is the operator (A-sI) nilpotent? ('I' is the...
  16. J

    Need to find eigenvector that corresponds to max eigenvalue

    To give you some background, I am trying to perform an AHP calculation using Java code. I have a 15x15 matrix and I need to find its eigenvector. I want the eigenvector that corresponds to the greatest eigenvalue. Let's say I already have some method that gives me all the eigenvectors and all...
  17. F

    Eigenvalue of momentum for particle in a box

    The wave function of "particle in a box" is Asin(kx). Since potential energy is zero inside the box, so the Hamiltonian is just kinetic energy In principle, I should be able to find eigenvalue of momentum using momentum operator, but stymied in solving the equation. Can somebody help me find...
  18. N

    Why eigenvalue specification reduces the no. of LI equations?

    Hi everyone, I am stuck with the following for last couple of days. Many books mention during the development in the idea of Eigenvalue problem: say, you have the equation [\ A-\lambda\ I]\ X=\ 0 where A is an NxN matrix and X is an Nx1 vector. The above consists of n equations.Say,all...
  19. A

    Eigenvalue formulation to find the principal stresses, directions

    Homework Statement 3.) Stress analysis at a critical point in a machine member gives the three-dimensional state of stress in MPa as the following: y = [ 105 0 0 0 -140 210 0 210 350 ]...
  20. D

    COMSOL - parameter dependent eigenvalue calculations

    Hello, I am using COMSOL (RF modul) for some time now to calculate the eigenvalues (modes) of optical fibers. So far I changed all the params from hand in the software. But it is getting anoying to change a parameter (the wavelength) and to recalculate if one wants to calculate for many...
  21. S

    Is 1/λ an Eigenvalue of the Inverse of A?

    How do I prove that if A is an invertible matrix and lambda does not equal zero then one dived by lambda is an eigenvalue of the inverse of A?
  22. K

    Eigenvalue problem using Bessel Functions

    Homework Statement Bessels equation of order n is given as the following: y'' + \frac{1}{x}y' + (1 - \frac{n^2}{x^2})y = 0 In a previous question I proved that Bessels equation of order n=0 has the following property: J_0'(x) = -J_1(x) Where J(x) are Bessel functions of...
  23. E

    Orthogonal Transformations with Eigenvalue 1

    Homework Statement Prove that an orthogonal transformation T in Rm has 1 as an eigenvalue if the determinant of T equals 1 and m is odd. What can you say if m is even? The attempt at a solution I know that I can write Rm as the direct sum of irreducible invariant subspaces W1, W2, ..., Ws...
  24. B

    Find 2 linearly independent eigenvectors and a eigenvalue

    Hi I am supposed to, without calculation, find 2 linearly independent eigenvectors and a eigenvalue of the following matrix A 5 5 5 5 5 5 5 5 5 The eigenvalue is easy -- it is 15. And I can find one eigenvector, [1 1 1] (written vertically), but another without calculation? Is there...
  25. F

    What Eigenvalues Lead to Square-Integrable Eigenfunctions?

    Homework Statement solve the eigenvalue problem ∫(-∞)x dx' (ψ(x' ) x' )=λψ(x) what values of the eigenvalue λ lead to square-integrable eigenfunctions? The Attempt at a Solution ∫(-∞)xdx' (ψ(x' ) x' )=λψ(x) differentiate both sides to get ψ(x)x=λ d/dx ψ(x) ψ(x)x/λ=...
  26. I

    Eigenfunction and Eigenvalue of momentum operator

    Homework Statement Find all eigenfunction of momentum operator in x(px=h/i*d/dx) and their eigenvalues. Homework Equations operator*eigenfunction=eigenvalue*eigenfunction Operator=px The Attempt at a Solution I really don't have any clues Thank you
  27. T

    Eigenvalue question, hermitian matrix

    I read from a book and claim that for any hermitian matrix can be diagonalized by a unitary matrix whose columns represent a complete set of its normalized eigenvectors. It then given an equation...
  28. P

    Bounday-Value Problem: Eigenvalue and Eigenfunctions

    Homework Statement This is the original question: \frac{d^{2}y}{dx^{2}}-\frac{6x}{3x^{2}+1}\frac{dy}{dx}+\lambda(3x^{2}+1)^{2}y=0 (Hint: Let t=x^{3}+x) y(0)=0 y(\pi)=02. The attempt at a solution This might be all wrong, but this is all I can think of \frac{dt}{dx}=3x^{2}+1 so...
  29. M

    Eigenvalue Problem Simplified: A Simple Solution to the Eigenvalue Problem

    Solve the eigenvalue problem \frac{d^2 \phi}{dx^2} = -\lambda \phi subject to \phi(0) = \phi(2\pi) and \frac{d \phi}{dx} (0) = \frac{d \phi}{dx} (2 \pi). I had the solution already, but am looking for a much simpler way, if any. EDIT: Sorry that I accidentally posted...
  30. J

    Eigenvalue kind of nilpotent problem

    If a vector v\in V and a linear mapping T:V\to V are fixed, and there exists numbers \lambda_1\in\mathbb{C}, n_1\in\mathbb{N} so that (T - \lambda_1)^{n_1}v = 0, is it possible that there exists some \lambda_2\neq\lambda_1, and n_2\in\mathbb{N} so that (T - \lambda_2)^{n_2}v = 0? (Here...
  31. K

    Why did Schrodinger call his equation eigenvalue problem?

    Why did Schrodinger call his equation eigenvalue problem? We can solve Schrodinger equation since it's just differential equation with complex number
  32. R

    What is the associated eigenvalue?

    Homework Statement V is an eigenvector of the nxn matrix A, with a eigenvalue of 4. explain why V is a eigenvector of A^2+2A+3I. what is the associated eigenvalue? Homework Equations The Attempt at a Solution is the eigenvalue of A^2+2A+3I=21?
  33. F

    Finding Eigenvalues and Eigenspaces: A Reflection Transformation Example

    Homework Statement Let A be the matrix of the linear transformation T. Without writing A, find an eigenvalue of A and describe the eigenspace. T is the transformation on R2 that reflects points across some line through the origin. The Attempt at a Solution Since they tell us that...
  34. S

    Find a 2x2 Matrix A for Given Eigenspaces E_2 and E_4

    Find a 2\times 2 matrix A for which E_4 = span [1,-1] and E_2 = span [-5, 6] where E_(lambda) is the eigenspace associated with the eigenvalue (lambda) relevant equations: Av=(lambda)v The Attempt at a Solution I've pretty much gotten most of the eigenspace/value problems down, but this...
  35. S

    Finding the Multiplicity of Eigenvalues for a 2x2 Matrix with a Variable Element

    For which value of k does the matrix A= |4 k| |-7 -5| have one real eigenvalue of multiplicity 2? The Attempt at a Solution - I tried by setting this problem up with det(A-(lambda)I) and trying to solve like that, but I can't seem to get it that way either. I am getting...
  36. Q

    Solving Eigenvalue Problem for Operator d2/dx2 - bx2, Function psi=e^-ax2

    Homework Statement operator is d2/dx2 - bx2 function is psi=e^-ax2 if this fuction is eigenfuction for this operator, what is "a" and "b" constants value? Homework Equations The Attempt at a Solution
  37. J

    How to Prove the Eigenvalue Property of CrA(x)?

    I hava a problem finding out how this is showned If A is n x n and r is not 0. Show that CrA(x) = (r^n) * CA(x/r) What rule should I think of in defanition.
  38. E

    Good book to understand eigenvalue for quantum mechanics?

    Guys I read a little on how Heisenberg's quantum mechanics equations (solving with eigenvectors) were derived in the book "What is quantum mechanics: A physical adventure". There is no exercise in the book. After reading, I still don't understand eigenvalue. What is it for? How to use it...
  39. N

    Solving the Eigenvalue Problem: Proving \ e ^ A \psi=\ e ^\lambda\psi

    Homework Statement Consider the following problem: if \ A \psi=\lambda\psi,prove that \ e ^ A \psi=\ e ^\lambda\psi Homework Equations The Attempt at a Solution This is my attempt.Please check if I am correct. If \ e ^ A \psi=\ e ^\lambda\psi is correct, we should...
  40. S

    Eigenvalue of a rotation matrix

    cos a -sin a sin a cos a How do I find the eigenvalue of this rotation matrix? I did the usual way, but didn't work! Could someone tell me how to start this problem?
  41. M

    Proving Eigenvalues and Eigenvectors for T and T*: A Comprehensive Guide

    I know that if T has eigenvalue k, then T* has eigenvalue k bar. But if T has eigenvector x, does T* also have eigenvector x? If so, how do you prove it? I don't see that in my textbook.
  42. B

    Eigenfunction, Eigenvalue, Wave Function and collapse

    Reading Sam Treiman's http://books.google.de/books?id=e7fmufgvE-kC" he nicely explains the dependencies between the Schrödinger wave equation, eigenvalues and eigenfunctions (page 86 onwards). In his notation, eigenfunctions are u:R^3\to R and the wavefunction is \Psi:R^4\to R, i.e. in contrast...
  43. T

    In an experiment, do we measure the eigenvalue or expectation value?

    In an experiment, do we measure the eigenvalue or the expectation value ? If both can be measured, how can we distinguish one from another ?
  44. J

    Obtain an eigenvector corresponding to each eigenvalue

    Homework Statement The linear operator T on R^2 has the matrix [4 -5; -4 3] relative to the basis { (1,2), (0,1) } Find the eigenvalues of T. Obtain an eigenvector corresponding to each eigenvalue.Homework Equations The Attempt at a Solution I was able to find the eigenvalues (8 and -1)...
  45. R

    Interpreting Complex Eigenvalues in Comsol Analysis

    Hey, Im working with Comsol and doing some eigenvalue analysis. Why is sometimes the eigenvalues are complex numbers and not real number frequencies? How should I interpret these complex eigenvalues? Thanks
  46. M

    What is the method for solving the eigenvalue problem with integration by parts?

    Solve the eigenvalue problem O_{6} \Psi(x) = \lambda \Psi(x) O_{6}\Psi(x) = \int from negative infinity to x of dxprime *\Psi(xprime) * xprime what values of eigenvalue \lambda lead to square integral eigenfuctions? (Hint: Differentiate both sides of the equation with respect to x) Im...
  47. S

    Functions, operator => eigenfunction, eigenvalue

    [SOLVED] Functions, operator => eigenfunction, eigenvalue Homework Statement Show, that functions f1 = A*sin(\theta)exp[i\phi] and f2 = B(3cos^{2}(\theta) - 1) A,B - constants are eigenfunctions of an operator http://img358.imageshack.us/img358/3406/98211270ob1.jpg and find...
  48. J

    Solving 1D/2D Eigenvalue Equation for Proving Function

    Hello, I want to prove that the function \mathcal{A} in the 1D case satisfy \mathcal{A}=\frac{48}{m}\sum_{j=1}^\infty \frac{\sin^2(qj/2)}{j^5}=\frac{12}{m}\left[2\zeta(5)-\text{Li}_5(e^{iq})-\text{Li}_5(e^{-iq})\right], with \text{Li}_n(z) the polylogarithm function, and the matrix...
  49. D

    Energy eigenvalue and eigen vector

    I have some question on energy eigenvalue and eigenfunction help please A particle, mass m , exists in 3 dimensions, confined in the region 0< x < 2L, 0 < y < 3L, 0 < z < 3L a) what are the energy eigenvalues and eigenfunctions of the particle? b) if the particel is a...
  50. T

    Solving WKB Eigenvalue Problem for Bound States

    Hi, This is just a quick question -- I'm puzzled by the way this answer sheet represents the potential function. The question asks us to determine the energy eigenvalues of the bound states of a well where the potential drops abruptly from zero to a depth Vo at x=0, and then increases...
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