If u=⟨1,2,3⟩\mathbf{u} = \langle 1, 2, 3 \rangleu=⟨1,2,3⟩, what is 2u2\mathbf{u}2u?
⟨3,4,5⟩\langle 3, 4, 5 \rangle⟨3,4,5⟩
⟨2,2,3⟩\langle 2, 2, 3 \rangle⟨2,2,3⟩
⟨2,4,6⟩\langle 2, 4, 6 \rangle⟨2,4,6⟩
⟨1,4,9⟩\langle 1, 4, 9 \rangle⟨1,4,9⟩