Isometries in R^nExplores the standard form of isometries in R^n and the preservation of distances.
Projections and SymmetriesExplores projections on lines and symmetries in 2D space, emphasizing fixed points and symmetric matrices.
Principal Axes TheoremExplains the Principal Axes Theorem for symmetric matrices and quadratic forms, showing the existence of orthogonal matrices for diagonalization.