Given u=⟨1,−1⟩\mathbf{u} = \langle 1, -1 \rangleu=⟨1,−1⟩ and v=⟨1,1⟩\mathbf{v} = \langle 1, 1 \ranglev=⟨1,1⟩, what is the angle between them?
0°0°0°
45°45°45°
90°90°90°
180°180°180°