Inner products and the spectral theorem (intro)
Orthonormal bases
Linear algebra · Theoretical / proof-based
Topic
Orthonormal bases
Practice by unit: Inner products and the spectral theorem (intro)
Undergraduate Linear Algebra — scope drawn from Axler Linear Algebra Done Right (open PDF), Treil Linear Algebra Done Wrong, Beezer A First Course in Linear Algebra, and AIM-approved OER texts.