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Eigenvalues and Eigenvectors 3×3 Matrix Calculator

This calculator finds the eigenvalues and eigenvectors of a 3×3 matrix. It’s ideal for students, engineers, and scientists working with linear algebra, physics, and advanced mathematics where matrix diagonalization and spectral analysis are required.

3×3 Matrix Eigenvalues and Eigenvectors Solver

Input Fields
a11
a12
a13
a21
a22
a23
a31
a32
a33
If enabled, the result will update automatically when you change any value.

Eigenvalues and Eigenvectors Formula for 3×3 Matrix

Formula
$$ \det(A – \lambda I) = 0 \\[1em] (A – \lambda I) \vec{v} = 0 $$

Where:

  • $$A$$ is the 3×3 matrix
  • $$\lambda$$ represents an eigenvalue
  • $$I$$ is the identity matrix
  • $$\vec{v}$$ is the corresponding eigenvector

The characteristic equation $$\det(A – \lambda I) = 0$$ is solved for $$\lambda$$, and the resulting $$\lambda$$ values are used to compute the eigenvectors by solving the homogeneous system.

Eigenvalues and Eigenvectors 3×3 – Calculation Example

$$A = \begin{bmatrix} 6 & 2 & 1 \\ 2 & 3 & 1 \\ 1 & 1 & 1 \end{bmatrix} $$

Solve:
$$\det(A – \lambda I) = 0 $$

Characteristic polynomial:
$$\lambda^3 – 10 \lambda^2 + 27 \lambda – 18 = 0 $$

Solutions (eigenvalues):
$$\lambda_1 = 1, \quad \lambda_2 = 3, \quad \lambda_3 = 6$$

Find eigenvectors by solving:
$$(A – \lambda I)\vec{v} = 0$$

for each \(\lambda\).

Eigenvalues and eigenvectors are key in linear transformations, stability analysis, vibration modes, and quantum mechanics. Our calculator simplifies the process of solving the characteristic equation and finding eigenvectors for any 3×3 matrix.

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