When can a matrix not be diagonalized?

In general, any 3 by 3 matrix whose eigenvalues are distinct can be diagonalised. 2. If there is a repeated eigenvalue, whether or not the matrix can be diagonalised depends on the eigenvectors. (i) If there are just two eigenvectors (up to multiplication by a constant), then the matrix cannot be diagonalised.
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How do you determine if a matrix Cannot be diagonalized?

To diagonalize A :
  1. Find the eigenvalues of A using the characteristic polynomial.
  2. For each eigenvalue λ of A , compute a basis B λ for the λ -eigenspace.
  3. If there are fewer than n total vectors in all of the eigenspace bases B λ , then the matrix is not diagonalizable.
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Can all matrix be diagonalized?

In general, a rotation matrix is not diagonalizable over the reals, but all rotation matrices are diagonalizable over the complex field.
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What are the conditions for a matrix to be diagonalizable?

A linear map T: V → V is diagonalizable if and only if the sum of the dimensions of its eigenspaces is equal to dim(V), which is the case if and only if there exists a basis of V consisting of eigenvectors of T. With respect to such a basis, T will be represented by a diagonal matrix.
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Which matrices are diagonalizable?

A square matrix is said to be diagonalizable if it is similar to a diagonal matrix. That is, A is diagonalizable if there is an invertible matrix P and a diagonal matrix D such that. A=PDP^{-1}.
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Not diagonalizable



Is every matrix diagonalizable over C?

No, not every matrix over C is diagonalizable. Indeed, the standard example (0100) remains non-diagonalizable over the complex numbers.
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Is a matrix diagonalizable if 0 is an eigenvalue?

See the post “Determinant/trace and eigenvalues of a matrix“.) Hence if one of the eigenvalues of A is zero, then the determinant of A is zero, and hence A is not invertible. The true statement is: a diagonal matrix is invertible if and only if its eigenvalues are nonzero.
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How do you determine if a 3x3 matrix is diagonalizable?

A matrix is diagonalizable if and only of for each eigenvalue the dimension of the eigenspace is equal to the multiplicity of the eigenvalue. For the eigenvalue 3 this is trivially true as its multiplicity is only one and you can certainly find one nonzero eigenvector associated to it.
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Can a matrix be diagonalizable and not invertible?

No. For instance, the zero matrix is diagonalizable, but isn't invertible.
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Is a zero matrix diagonalizable?

The zero-matrix is diagonal, so it is certainly diagonalizable.
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Is a symmetric matrix always diagonalizable?

Real symmetric matrices not only have real eigenvalues, they are always diagonalizable.
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Which one of the following matrix is not diagonalizable?

Solution: The characteristic equation det(A − λI) = 0 has eigenvalues λ1 = −1, λ2 = 2, λ3 = 2. Corresponding to the repeated eigenvalue 2, we must have two linearly independent eigenvectors. Otherwise, A is not diagonalizable.
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For what values of k is the matrix not diagonalizable?

Therefore, the matrix is not diagonalizable for k=0.
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How do you know if a matrix is defective?

In linear algebra, a defective matrix is a square matrix that does not have a complete basis of eigenvectors, and is therefore not diagonalizable. In particular, an n × n matrix is defective if and only if it does not have n linearly independent eigenvectors.
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Can a matrix with one eigenvalues be diagonalizable?

Yes, it is possible for a matrix to be diagonalizable and to have only one eigenvalue; as you suggested, the identity matrix is proof of that. But if you know nothing else about the matrix, you cannot guarantee that it is diagonalizable if it has only one eigenvalue.
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Are 2x2 matrices always diagonalizable?

If it has distinct eigenvalue, the matrix is diagonizable, but the reverse is not always true. But it is true that a 2 x 2 non-diagonal matrix is diagonalizable IFF it has two distinct eigenvalues (which is what the OP was asking, I believe), since a scalar matrix is similar only to itself.
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What does it mean if a matrix is diagonalizable?

A diagonalizable matrix is any square matrix or linear map where it is possible to sum the eigenspaces to create a corresponding diagonal matrix. An n matrix is diagonalizable if the sum of the eigenspace dimensions is equal to n.
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Which of the following matrix is not diagonalizable Mcq?

λ = 0 has algebraic multiplicity 2 whereas its geometric multiplicity is 1. Hence, P is not diagonalisable.
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Can non symmetric matrices be diagonalized?

Equivalently, a square matrix is symmetric if and only if there exists an orthogonal matrix S such that ST AS is diagonal. That is, a matrix is orthogonally diagonalizable if and only if it is symmetric. 3. A non-symmetric matrix which admits an orthonormal eigenbasis.
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Can skew symmetric matrix be diagonalizable?

So in particular, every symmetric matrix is diagonalizable (and if you want, you can make sure the corresponding change of basis matrix is orthogonal.) For skew-symmetrix matrices, first consider [0−110]. It's a rotation by 90 degrees in R2, so over R, there is no eigenspace, and the matrix is not diagonalizable.
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Is orthogonal matrix diagonalizable?

An n×n matrix A is said to be orthogonally diagonalizable when an orthogonal matrix P can be found such that P−1AP = PT AP is diagonal. This condition turns out to characterize the symmetric matrices. The following conditions are equivalent for an n×n matrix A. 1.
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Are skew Hermitian matrices diagonalizable?

Furthermore, skew-Hermitian matrices are normal. Hence they are diagonalizable and their eigenvectors for distinct eigenvalues must be orthogonal. All entries on the main diagonal of a skew-Hermitian matrix have to be pure imaginary; i.e., on the imaginary axis (the number zero is also considered purely imaginary).
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Why only symmetric matrices are orthogonally diagonalizable?

Therefore, every symmetric matrix is diagonalizable because if U is an orthogonal matrix, it is invertible and its inverse is UT. In this case, we say that A is orthogonally diagonalizable. Therefore every symmetric matrix is in fact orthogonally diagonalizable.
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