Unit 6 · Symmetric Matrices, Positive Definiteness, and the SVD
Chapter 6.1
Symmetric and Positive Definite Matrices
Symmetry buys the best possible spectral news: real eigenvalues and orthonormal eigenvectors. Positive definiteness adds energy — xᵀAx > 0 — and four equivalent tests for it.
13–16 min · in preparation · lesson 16 of 21
By the end
- 01State and use the spectral theorem S = QΛQᵀ
- 02Test positive definiteness by pivots, eigenvalues, determinants, and energy
- 03Connect positive definiteness to minima and ellipsoids