### Why symmetric matrices are diagonalizable?

## Why symmetric matrices are diagonalizable?

The Spectral Theorem: A square matrix is symmetric if and only if it has an orthonormal eigenbasis. 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.

**What is unitarily diagonalizable?**

Recall the definition of a unitarily diagonalizable matrix: A matrix A ∈ Mn. is called unitarily diagonalizable if there is a unitary matrix U for which. U*AU is diagonal. A simple consequence of this is that if U*AU = D. (where D = diagonal and U = unitary), then.

**Is a complex symmetric matrix diagonalizable?**

symmetric matrices are similar, then they are orthogonally similar. It follows that a complex symmetric matrix is diagonalisable by a simi- larity transformation when and only when it is diagonalisable by a (complex) orthogonal transformation.

### Is every 2×2 symmetric matrix diagonalizable?

Is every 2×2 matrix diagonalizable? – Quora. The short answer is NO. In general, an nxn complex matrix A is diagonalizable if and only if there exists a basis of C^{n} consisting of eigenvectors of A. By the Schur’s triangularization theorem, it suffices to consider the case of an upper triangular matrix.

**Is every real symmetric matrix Unitarily diagonalizable?**

Theorem: Every real n × n symmetric matrix A is orthogonally diagonalizable Theorem: Every complex n × n Hermitian matrix A is unitarily diagonalizable. Theorem: Every complex n × n normal matrix A is unitarily diagonalizable.

**Can a singular matrix be diagonalizable?**

Yes, diagonalize the zero matrix.

## Can a real matrix be unitarily diagonalizable?

A matrix A is called unitarily diagonalizable if A is similar to a diagonal matrix D with a unitary matrix P, i.e. A = PDP∗. Theorem: Every real n × n symmetric matrix A is orthogonally diagonalizable Theorem: Every complex n × n Hermitian matrix A is unitarily diagonalizable.

**Is normal matrix always diagonalizable?**

All Hermitian matrices are normal but have real eigenvalues, whereas a general normal matrix has no such restriction on its eigenvalues. All normal matrices are diagonalizable, but not all diagonalizable matrices are normal.

**Are complex symmetric matrices normal?**

In the taxonomy at https://en.wikipedia.org/wiki/List_of_matrices, it says that complex symmetric matrices are normal. For real symmetric matrices, you can prove that they are hermitian hence normal.

### Is every complex matrix is diagonalizable?

Every matrix is not diagonalisable. Take for example non-zero nilpotent matrices.

**How do you know if a 2×2 matrix is diagonalizable?**

A matrix is diagonalizable if and only if for each eigenvalue the dimension of the eigenspace is equal to the multiplicity of the eigenvalue. Meaning, if you find matrices with distinct eigenvalues (multiplicity = 1) you should quickly identify those as diagonizable.

**Is it true that all symmetric matrices are diagonalizable?**

Of course, the result shows that every normal matrix is diagonalizable. Of course, symmetric matrices are much more special than just being normal, and indeed the argument above does not prove the stronger result that symmetric matrices are orthogonaly diagonalizable.

## Which is an example of a unitarily diagonalized matrix?

Matrix is unitarily diagonalizable. That is, there exists a unitary matrix ) such that The proofs of 1 and 2 are almost the same as in Theorem 5.4.1 a and b. The difference is that is used instead of and in , . Example 6 Can be unitarily diagonalized? If so, perform the diagonalization. Because is hermitian, it can be unitarily diagonalized.

**Are there any special properties of normal matrices?**

Normal Matrices. Normal matrices are matrices that include Hermitian matrices and enjoy several of the same properties as Hermitian matrices. Indeed, while we proved that Hermitian matrices are unitarily diagonalizable, we did not establish any converse. That is, if a matrix is unitarily diagonalizable, then does it have any special property

**What happens when a Hermitian matrix is diagonalized?**

When a hermitian matrix is diagonalized, the set of orthonormal eigenvectors of is called the set of principal axes of and the associated matrix is called a principal axis transformation. For a real hermitian matrix, the principal axis transformation allows us to analyze geometrically.

Why symmetric matrices are diagonalizable? The Spectral Theorem: A square matrix is symmetric if and only if it has an orthonormal eigenbasis. 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…