Same Angle; Same Dot Product

The two vectors that have a dot product of -0.866 with q_u = (0.0, 1)^T are:

• z_u = (-0.5, -0.866)^T
• v_u = ( 0.5, -0.866)^T

In the diagram, the two have their tail placed at the origin. (But remember: vectors are not fixed to any particular location and can be drawn anywhere that is convenient). The dot product gives you the angle between the orientation of two vectors.