3. (3.1) Which of the following are meaningful? Which are meaningless? Explain. (a) (u . v) . w (b) (u . v)w (c) lull(v . w) (d) u . ( v tw) (e) (u . v) + w (f) lull . (v + w) 4. (3.7b) Find the vector projection of v onto b, where v = (4, 2, 0) and b = (1, 1, 1)