Eigenvalue Calculator

Find eigenvalues & eigenvectors

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About Eigenvalue Calculator

An eigenvalue calculator that finds eigenvalues and eigenvectors for 2×2 and 3×3 square matrices. Shows the characteristic polynomial det(A−λI)=0, trace, determinant, and verifies Av=λv. All calculations are client-side. Essential for linear algebra, quantum mechanics, principal component analysis, and differential equations.

Eigenvalue Calculator Features

  • 2×2 and 3×3
  • Eigenvectors
  • Char. polynomial
  • Trace/Det
  • Verify Av=λv
Eigenvalues λ satisfy det(A−λI) = 0. For a 2×2 matrix, this gives a quadratic; for 3×3, a cubic. Once eigenvalues are found, eigenvectors come from solving (A−λI)v = 0. Key: trace = sum of eigenvalues, determinant = product of eigenvalues.

How to Use

Enter a square matrix:

  • Size: 2×2 or 3×3
  • Values: Fill entries
  • Result: Eigenvalues and eigenvectors

Properties

  • Trace = λ₁ + λ₂ + ...
  • Det = λ₁ × λ₂ × ...
  • Symmetric → real eigenvalues

Applications

PCA (data science), Google PageRank, quantum states, stability analysis, vibration modes, facial recognition.

Step-by-Step Instructions

  1. 1Choose 2×2 or 3×3.
  2. 2Enter matrix values.
  3. 3View eigenvalues.
  4. 4Check eigenvectors.
  5. 5Verify trace and determinant.

Eigenvalue Calculator — Frequently Asked Questions

Can eigenvalues be complex?+

Yes! Non-symmetric matrices can have complex eigenvalues, which always come in conjugate pairs (a±bi). Symmetric matrices always have real eigenvalues.

What does an eigenvector represent?+

A direction that doesn't change under the transformation — it only gets scaled by the eigenvalue. Av = λv means v stays in the same direction, scaled by λ.

Why are eigenvalues important in data science?+

PCA uses eigenvalues to find the most important directions in data. The largest eigenvalue corresponds to the direction of greatest variance.

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