Now, cos θ = -0.866. So θ = arc cos -0.866 = 150°.

**q _{u}** = (0.0, 1)

The angle between the two vectors is greater than 90°, so the cosine is negative.

In the diagram above, mentally draw *the other* vector that
has a dot product of -0.866 with vector **q _{u}**.