Linear Algebra and Its Applications · Problem 3.4.8
Orthogonality — Gilbert Strang
Mathematics · projection-non-orthogonal-vectors
Problem
Project the vector b=(1,2) onto two vectors that are not orthogonal, a1=(1,0) and a2=(1,1). Show that, unlike the orthogonal case, the sum of the two one-dimensional projections does not equal b.