Dot Products of Non-Unit Vectors
Suppose V and W are not (necessarily) unit vectors. What is VW? Hint:
What about V/|V| and W|W|? They're unit vectors. So what's V/|V|W|W|? Cos t. So what's VW? V/|V|W/|W| = Cos t, so VW = |V||W| Cos t.
Big formula of the section: VW = |V||W| Cos t M
which is true for all vectors, V and W, unit or not.