Chapter 6.4, Problem 90E

To determine

a)

To explain:

The angle $\theta$ between two non-zero vectors u and v, if $\text{u}\cdot \text{v}=0$.

To determine

b)

To explain:

The angle $\theta$ between two non-zero vectors u and v, if $\text{u}\cdot \text{v}>0$.

To determine

c)

To explain:

The angle $\theta$ between two non-zero vectors u and v, if $\text{u}\cdot \text{v}<0$.