orthogonal diagonalization


Summary

Spectral theorem, symmetry

Eigenspaces are orthogonal

Equivalent statements for orthogonal diagonalizability

Shortcut for the determinant of symmetric matrices, using submatrices

Concept

Orthogonal diagonalization

  • breaking up a complex transformation into a rotation, scale and then reverse rotation

is a rotation matrix

Spectral theorem

the converse is out of scope for MA1522

Orthogonality of eigenspaces

  • for symmetric matrices

only perform Gram-Schmidt for vectors within each eigenspace, the eigenspaces are already orthogonal

Application