Change of basis Definition and 99 Threads

  1. B

    Linear Mapping T: P2 to P2 with Basis B | Homework Help & Solution Explained"

    Homework Statement Problem is assuming the mapping T: P2---->P2 defined by T(a0+a1t+a2t2)=3a0+(5a0-2a1)t+(4a1+a2)t^2 is linear. Find the matrix representation of T relative to Basis B={1,t,t^2}. The part that I am confused on is when I go plug in the basis values T(1),T(t),and T(t^2)? I don't...
  2. B

    Change of basis of density matrix

    I have a density matrix in one basis and need to change it to another. I know the eigenvectors and eigenvalues of the basis I want to change to. How do I do this? Any help really appreciated- thanks!
  3. shounakbhatta

    Understanding Change of Basis Vector: What it is and How to Use It

    Hello, I am doing calculation on change of basis vector. But I am unable to understand why we do it. I mean to say what is the use of it and where in physics or maths it is used. Can anybody please explain it?
  4. S

    How unitary change of basis related to Trace?

    Homework Statement Shanker 1.7.1 3.)Show that the trace of an operator is unaffected by a unitary change of basis (Equivalently, show TrΩ=TrU^{\dagger}ΩUHomework Equations I can show that via Shanker's hint, but I however can't see how a unitary change of basis links to TrΩ=TrU^{\dagger}ΩU...
  5. J

    Linear transformation and Change of Basis

    Homework Statement Greetings, I have been stuck with this problem for a while, I thought maybe someone could give me some advice about it. Thanks a lot in advance. If T is a linear transformation that goes from R^2 to R^2 given that T(v1)= -2v2 -v1 and T(v2)=3v2. and B =...
  6. A

    What Am I Missing in Change of Basis Matrices?

    Homework Statement https://dl.dropbox.com/u/4788304/Screen%20shot%202012-07-08%20at%2002.53.44.JPG This is the solution of Problem A.15 in Griffiths' Quantum Mechanics. Tx is the rotation matrix about x-axis for theta degrees; while Ty is the rotation matrix about y-axis for theta degrees...
  7. K

    Pseudoinverse - change of basis?

    Hello, I was wondering if the pseudoinverse can be considered a change of basis? If an m x n matrix with m < n and rank m and you wish to solve the system Ax = b, the solution would hold an infinite number of solutions; hence you form the pseudoinverse by A^T(A*A^T)^-1 and solve for x to...
  8. T

    Is Change of Basis the Solution to My Linear Algebra Problem?

    Homework Statement The Attempt at a Solution So first I thought to myself that the proper way of doing this problem was to construct each of the standard basis vectors as a linear combination of the basis given us. I have, T(1,0,0) = \frac{1}{2} T(1,0,1) + \frac{1}{2} T(1,0,-1) =...
  9. T

    Change of Basis between different size spaces

    Hi, I'm working on an example question with the following info: \alpha = {(3,0,1) , (3,1,1), (2,1,1)} \beta = {(1,1), (1,-1)} Are a set of bases. [T]\beta\alpha = \begin{bmatrix} 1 & 2 & -1\\ 0 & 1 & -1 \end{bmatrix} Now they go on to say: Let T: R3--> R3 be the transformation whose...
  10. matqkks

    Change Basis: Reasons to Write Vector in Rn Other Than Standard Basis

    Why should we want to write a vector in Rn in other than standard basis? A normal application of linear transformations in most textbooks is converting a given vector in standard basis to another basis. This is sometimes a tedious task. Why carry out this task? Thanks for your replies in advance.
  11. A

    Exploring Change of Basis Matrices and Intuitive Examples in Linear Algebra

    Given a basis A = {a1,a2...an} we can always translate coordinates originally expressed with this basis to another basis A' = {a1',a2'...an'}. To do this we simply do some matrix-multiplication and it turns out that the change of basis matrix equals a square matrix whose rows are the coordinates...
  12. L

    Change of basis matrix(linear algebra)

    Hi I'm stuck on this problem and I could not find similar examples anywhere.. any help would be greatly appreciated, thank you. Homework Statement Compute the change of basis matrix that takes the basis V1 = \begin{bmatrix} -1 \\ 3 \end{bmatrix} V2 = \begin{bmatrix} 2 \\ 5 \end{bmatrix}...
  13. B

    Orthogonal change of basis preserves symmetry

    Homework Statement Prove that symmetric and antisymmetric matrices remain symmetric and antisymmetric, respectively, under any orthogonal coordinate transformation (orthogonal change of basis): Directly using the definitions of symmetric and antisymmetric matrices and using the orthogonal...
  14. Q

    By multiplying both sides by P.

    Homework Statement lets say i have a matrix A which is symmetric i diagonalize it , to P-1AP = D Question 1) am i right to say that the principal axis of D are no longer cartesian as per matrix A, but rather, they are now the basis made up of the eigen vectors of A? , which are the columns...
  15. T

    Change of Basis Matrix for R2: B1 to B2

    Homework Statement B1 = {[1,2], [2,1]} is a basis for R2 B2 = {[1,-1], [3,2]} is a basis for R2 Find the change of basis matrix from B1 to B2 Homework Equations [B2 | B1] The Attempt at a Solution For some reason I can not solve this. I keep ending up with the matrix...
  16. P

    Understanding Change of Basis in Vector Spaces

    hi.. can anyone say what is the concept behind change of basis.. y do we change a vector of one basis to another?
  17. G

    Understanding Change of Basis in N-Dimensional Space

    Homework Statement Could someone help me understand the following manipulations concerning change of babsis in an N-dimensional space: |i'\right\rangle=R|i\right\rangle=\sum_{j=1}^NR_{ji}|j\right\rangle multiply around by (R^{-1})_{ik}...
  18. P

    Change of Basis + Geometric, Algebraic Multiplicities

    Making a change of basis in the matrix representation of a linear operator will not change the eigenvalues of that linear operator, but could making such a change of basis affect the geometric multiplicities of those eigenvalues? I'm thinking that the answer is "no", it cannot.. Since if...
  19. mccoy1

    Linear Algebra: Change of basis

    (a) Let A (matrix) =c1= [1,2,1], c2 = [0,1,2], c3 = [3,-2,-1] be a matrix (c1,c2,c3 refer to the columns of the matrix A, which is a 3x3 matrix) expressed in the standard basis and let w1 = (0,0,1)T, w2 = (0,1,2)T , w3 =(3,0,2)T , find the vector AUE in w basis. (b). Referring to problem (a)...
  20. T

    Change of Basis Matrices for B1 and B2 in Vector Space V - Homework Solution

    Homework Statement Let B1 = {v1; v2; v3} be a basis of a vector space V and let B2 = {w1;w2;w3} where w1 = v2 + v3 ; w2 = v1 + v3 ; w3 = v1 + v2 Verify that B2 is also a basis of V and find the change of basis matrices from B1 to B2 and from B2 to B1. *Use the appropriate change of basis matrix...
  21. Q

    Change of Basis Homework: Solving System of Equations

    Homework Statement We are given 2 bases for V = \Re_{1 x 3}. They are \beta_{1} = \begin{bmatrix} 2 & 3 & 2\end{bmatrix} \beta_{2} = \begin{bmatrix} 7 & 10 & 6\end{bmatrix} \beta_{3} = \begin{bmatrix} 6 & 10 & 7\end{bmatrix} and, \delta_{1} = \begin{bmatrix} 1 & 1 &...
  22. P

    Testing Change of Basis in Linear Operator

    I just want to test/verify my knowledge of change of basis in a linear operator.. (it's not a homework question). Suppose I have linear operator mapping R^2 into R^2, and expressed in the canonical basis (1,0), (0,1). Suppose (for the sake of discussion) that the linear operator is given by...
  23. I

    Change of basis in R^n and dimension is <n

    Suppose I have a basis for a subspace V in \mathbb{R}^{4}: \mathbf{v_{1}}=[1, 3, 5, 7]^{T} \mathbf{v_{2}}=[2, 4, 6, 8]^{T} \mathbf{v_{3}}=[3, 3, 4, 4]^{T} V has dimension 3, but is in \mathbb{R}^{4}. How would one switch basis for this subspace, when you can't use an invertible...
  24. L

    What is the matrix of T with respect to the basis (2,1),(1,-2)?

    Homework Statement Recall that the matrix for T: R^{2} \rightarrow R^{2} defined by rotation through an angle \theta with respect to the standard basis for R^{2} is \[A =\begin{array}{cc}cos \theta & -sin \theta \\sin \theta & cos\theta \\\end{array}\]\right] a) What is the matrix of T...
  25. T

    Linear Algebra - Bilinear Forms and Change of Basis

    Homework Statement Find the matrix of f relative to Alpha' and Beta'. Alpha' = [(1,0,0), (1,1,0), (2,-1,1)] Beta' = [(-13,9), (10,-7)] The question originally reads that f is a bilinear form. I've found a (correct according to answer key) matrix A that is 3 -4 4 -5 -1 2...
  26. N

    Representations and change of basis

    Hi guys 1) We are looking at a Hamiltonian H. I make a rotation in Hilbert space by the transformation {\cal H} = \mathbf a^\dagger\mathsf H \mathbf a = \mathbf a^\dagger \mathsf U\mathsf U^\dagger\mathsf H \mathsf U\mathsf U^\dagger\mathbf a = \mathbf b^\dagger...
  27. Z

    Linear Algebra- Quadratic form and change of basis

    Homework Statement Suppose that for each v = (x1, x1, ... xn) in Rn, q(v) = XTAX for the given matrix A. For the given basis B of Rn, find the expression for q(v) in terms of the coordiantes yi of v relative to B. a) A =...
  28. Z

    Linear Algebra - Change of basis matrices and RREF question what in the world?

    Linear Algebra - Change of basis matrices and RREF question what in the world?? Homework Statement Suppose the linear transformation T: P3 -> P2, over R has the matrix A = \begin{bmatrix}1&2&0&0\\0&1&2&1\\1&1&1&1 \end{bmatrix}...
  29. Z

    Linear Algebra - Change of basis question

    Homework Statement Let A = E4 in R4 (standard basis) and B = {x^2, x, 1} in P2 over R. If T is the linear transformation that is represented by \begin{bmatrix}1 & 1 & 0 & 1\\0 & 0 & 1 & -1\\1 & 1 & 0 & 1 \end{bmatrix} relative to A and B, find...
  30. Z

    Linear algebra - change of basis matrix

    Homework Statement Let A = {(1, 1), (2,0)} and B = {(0, 2), (2, 1)} in R2. a) Find [u]A (u with respect to A) if [u]B = [3, -2]. Homework Equations The Attempt at a Solution I tried to find [I]AB (transition matrix from B to A), then apply to [u]B, but couldn't represent (2, 1)...
  31. B

    Yes, it looks correct. Good job!

    Homework Statement Let {e1,e2,e3} be a basis for the vector space V, and T:V \rightarrow V a linear transformation. let f1 ;= e1 f2;=e1+e2 f3;=e1+e2+e3 Find the Matrix B of T with respect to {f1,f2,f3} given that the matrix with respect to {e1,e2,e3} is \[ \left(...
  32. S

    Linear Algebra - Linear Transformations, Change of Basis

    Homework Statement I need to prove this formula, but I'm not sure how to prove it.[T]C = P(C<-B).[T]B.P(C<-B)-1 whereby B and C are bases in finite dimensional vector space V, and T is a linear transformation. Your help is greatly appreciated! Homework Equations T(x)=Ax [x]C=P(C<-B)[x]B...
  33. D

    Linear Algebra (Change of Basis)

    Homework Statement Let E={1, x, x2,x3} be the standard ordered basis for the space P3. Show that G={1+x,1-x,1-x2,1-x3} is also a basis for P3, and write the change of basis matrix S from G to E. Homework EquationsThe Attempt at a Solution Here's what I got: S_E^G=\left( \begin{array}{cccc}...
  34. E

    Finding Orthonormal Bases for Metrics with Non-Zero Off-Diagonal Components

    I would like to know how, given a metric with non-zero off-diagonal components g_{mn}, m \neq n, one can find if another (orthonormal or null) frame exists in which g_{\mu \nu}=constant for all components of the metric. And if it exists how to compute this basis. Thanks!
  35. M

    Change of basis [ x ] B + [ y ] B = [ x+y ] B[

    change of basis [x]B + [y]B = [x+y]B[ Homework Statement Let B = {v1,...vn} be a basis for a vector space V, and let x = a1v1 + ... anvn and y = b1v1 + ...+ bnvn be arbitrary vectors in V. Find [x]B, [y]B and [x+y]B Homework Equations [x]B + [y]B = [x+y][SUB]B The Attempt at a...
  36. W

    Linear operators and a change of basis

    So...I've got an operator. Omega = (i*h-bar)/sqrt(2)[ |2><1| + |3><2| - |1><2| - |2><3| ] Part a asks if this is Hermitian, and my answer, unless I'm missing something, is no. Because the second part in square brackets is |1><2| + |2><3| - |2><1| - |2><3| which is not the same as Omega...
  37. K

    Linear Algebra - Change of Basis

    Homework Statement Let B & C be the following subsets of R^2 B= {[3 1] , [2 2]} (the vectors should be in columns instead of rows) C= {[1 0] , [5 4]} Let T: R^2 -> R^2 be the linear transformation whose matrix with respect to the basis B is [2 1] [1 5] (the brackets should be joint...
  38. N

    Change of basis- contravariant, covariant components of a vector.

    Homework Statement Let e_{i} with i=1,2 be an orthonormal basis in two-dimensional Euclidean space ie. the metric is g_{ij} = \delta _{ij}. In the this basis the vector v has contravariant components v^{i} = (1,2). Consider the new basis e_{1}^{'} = 5e_{1} - 2e_{2} e_{2}^{'} = 3e_{1} - e_{2}...
  39. E

    How to Find a New Basis for a Polynomial Representation in \(\mathcal{P}_3\)?

    Homework Statement In \mathcal{P}_3 with basis B = \langle 1 + x, 1 - x, x^2 + x^3, x^2 - x^3 \rangle we have this representation. \text{Rep}_B(1 - x + 3x^2 - x^3) = \begin{pmatrix} 0 \\ 1 \\ 1 \\ 2 \end{pmatrix}_B Find a basis D giving this different representation for the same...
  40. M

    Clebsch-Gordan coefficients for spin-one particle decomposition

    I started working on this topic and thought I would post it for other to contribute their ideas. The Clebsch-Gordan coefficients basically tell you how to move between two different representations of spin. I am trying to work them out logically. For starters I am doing the very simplest case...
  41. C

    Can a Change of Basis Simplify Linear Problems?

    Hello! I was wondering if someone can tell me about any application to change of basis... The application can be of any sort, though. Thanks!
  42. M

    Change of Basis Matrices for R2[x] with B and B

    consider the basis B={1,x,x^2} and B'={1,1-x,x^2-4x+2} for R2[x]. Find the change of basis matricses [id]B'toB and [id]BtoB' Really stuck on this! anyone can help me please?
  43. S

    Change of Basis: Finding PC<->B Matrix for V=R^2 with Given B and C

    find the change of basis matrix PC<->B from the given ordered basis B to the given ordered basis C of the vector space V: V=R^2; B={(-5,-3),(4,28)}; C={(6,2),(1,-1)} The Attempt at a Solution I'm having a hard time grasping the concept of changing basis. Can someone please...
  44. C

    Linear independence after change of basis

    Will a set of vectors stay linearly independent after a change of basis? If it's not always true then is it likely or would you need a really contrived situation?
  45. T

    Similarity and change of basis

    Homework Statement Consider the 2-dimensional complex vector space V of functions spanned by sin x and cos x. For a fixed real number α, define a linear operator T ≡ Tα on V by putting T(f(x)) = f(x + α). Find the matrices [T]B and [T]E of T relative to the bases B = {cos x, sin x} and E =...
  46. S

    Not clear about the change of basis in new space

    Actually after I wrote down the query on the invertible matrix which I posted a few days ago I happened to refer again to Kunze Huffman and found that this is a standard theorem regarding transformation of linear operator from one basis to another. Then I realized that the point which was...
  47. J

    Operator change of basis (QM / QI)

    Hi there, just doing some basic linear algebra for quantum computation / quantum information theory, and am wondering whether I'm changing the basis of an operator correctly. If I have two orthogonal basis vectors of space C2 given by (~ = complex conjugate): S1 = [|0>, |1>] and S2 =...
  48. Norman

    Change of Basis: Converting Wavefunction from S_z to S_x

    Hello all, I need some help... If I know the form of a wavefunction in the S_z basis, say it is spin up, how do I convert that to a wavefunction expressed in the S_x basis? Is there a very simple way to do this? Thanks
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