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Eigenvalues and Eigenvectors 2×2 Matrix Calculator

This calculator computes the eigenvalues and eigenvectors of a 2×2 matrix. It is perfect for students, engineers, and scientists working with linear algebra, physics, and systems analysis where eigen decomposition is required.

2×2 Matrix Eigenvalues and Eigenvectors Solver

Input Fields
a11
Matrix element at row 1, column 1
a12
Matrix element at row 1, column 2
a21
Matrix element at row 2, column 1
a22
Matrix element at row 2, column 2
If enabled, the result will update automatically when you change any value.

Eigenvalues and Eigenvectors Formula for 2×2 Matrix

Formula
$$ \det(A – \lambda I) = 0 \\[1em] (A – \lambda I) \vec{v} = 0 \\[1em] \det \begin{bmatrix} a – \lambda & b \\ c & d – \lambda \end{bmatrix} = 0 $$

Where:

  • $$A = \begin{bmatrix} a & b \\ c & d \end{bmatrix}$$ is the 2×2 matrix
  • $$\lambda$$ are the eigenvalues
  • $$\vec{v}$$ are the corresponding eigenvectors

The characteristic equation is solved for $$\lambda$$, then eigenvectors are found by solving the system $$(A – \lambda I)\vec{v} = 0$$.

Eigenvalues and Eigenvectors 2×2 – Calculation Example

$$A = \begin{bmatrix} 4 & 2 \\ 1 & 3 \end{bmatrix} $$

$$\det\begin{bmatrix} 4 – \lambda & 2 \\ 1 & 3 – \lambda \end{bmatrix} = (4 – \lambda)(3 – \lambda) – 2 \cdot 1 = \lambda^2 – 7 \lambda + 10 = 0 $$

Solutions (eigenvalues):
$$\lambda_1 = 5, \quad \lambda_2 = 2$$

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

for each $$\lambda$$.

Eigenvalues and eigenvectors of a 2×2 matrix are essential in solving systems of equations, stability analysis, and understanding linear transformations. Our calculator helps find them quickly and accurately, avoiding manual calculation errors.

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