Final answer:
The cosine of θ is equal to 1 for two parallel vectors.
Step-by-step explanation:
The cosine of θ is equal to 1 for two vectors when they are parallel to each other.
When two vectors are parallel, the angle between them is 0 degrees. In this case, the cosine of 0 degrees is 1, which means that the cosine of θ is equal to 1.
For example, if vector A = (3, 0) and vector B = (6, 0), they are parallel vectors because they have the same x-components and different y-components. The angle between them is 0 degrees, and the cosine of 0 degrees is 1.