1. (a) Let V ⊂ ℐ³ be a proper subspace of ℐ³ containing the vectors
(1, 1, -4), (1, -2, 2), (-3, -3, 12), (-1, 2, -2).
(i) Find a basis for V.
(ii) Find the number a ∈ ℐ such that the vector u = (2, 2, a) is orthogonal to V.
(b) Let W = span{(1, 2, 1), (0, -1, 2)}.
(i) Determine an orthonormal basis for W.
(ii) Compute pr_W((1, 1, 1)).