Documentation

Mathematica Teacher's Edition

Built-in Functions

Lists and Matrices

Matrix Operations

Eigenvalues

Eigenvalues[m] gives a list of the eigenvalues of the square matrix m.

Eigenvalues finds numerical eigenvalues if m contains approximate real or complex numbers.
Repeated eigenvalues appear with their appropriate multiplicity.
An matrix gives a list of exactly eigenvalues, not necessarily distinct.
See The Mathematica Book on the web: Section 1.8.3 and Section 3.7.9.
See also: Det, Tr.

Further Examples