ORTHOGONALITY AND LEAST SQUARES
Orthogonal Vectors Norm Unit Vector Orthonormal Vectors Orthogonal Complement Orthogonal Projection Cauchy-Schwarz Inequality Angle Between Two Vectors Gram-Schmidt Process QR Factorialization Transpose Symmetric and Skew-symmetric Matrices Orthogonal Matrices Least Squares Solutions Matrix of an Orthogonal Projection	Orthogonal Matrices How to Examples Exercise How to: Orthogonal matrices are square NxN matrices whose columns form an orthonormal basis for Rn. Some interesting properties of orthogonal matrices include:      1) If A and B are orthogonal, so is A*B      2) If A is orthogonal, so is inv(A)      3) inv(A) == A'      Examples: Exercise: