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Matrix Diagonalization

Matrix diagonalization checker. Enter A to find eigenvalues/vectors, test diagonalizability and output P and D—for similarity.

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P⁻¹ A P = D
space-separated entries, semicolon-separated rows, e.g. 1 2;3 4

📖 Tutorial|Matrix Diagonalization

1. Definition
A is diagonalizable if there exists invertible P with P⁻¹AP = D (D diagonal).
2. Symbols
SymbolMeaning
Pmatrix whose columns are eigenvectors
Ddiagonal matrix of eigenvalues
nsize of A
3. How this tool works
  • A is diagonalizable iff it has n linearly independent eigenvectors;
  • Columns of P are the eigenvectors;
  • Diagonal of D follows the column order of P.
4. Steps
  1. Enter A;
  2. Click Calculate to see eigenvalues and whether A is diagonalizable.
5. Example
Example: A=2 1;1 2. Eigenvalues 3,1 each have an eigenvector; P=[(1,1),(−1,1)], D=diag(3,1).
6. Pitfalls
Complex eigenvalues are not diagonalizable over R;
Repeated eigenvalues need enough independent eigenvectors;
Column order of P must match diagonal of D.

❓ FAQ|Matrix Diagonalization

When is A diagonalizable?
When it has n linearly independent eigenvectors.
Which matrices are always diagonalizable?
Real symmetric matrices are orthogonally diagonalizable.
How to build P and D?
Columns of P are eigenvectors; diagonal of D holds the corresponding eigenvalues.
Can complex eigenvalues be diagonalized?
Over C yes, over R no.
Why diagonalize?
It makes powers easy: A^k = P D^k P⁻¹.