# Math Help - Vectors dot prodoct question/clarification

1. ## Vectors dot prodoct question/clarification

In the following question, would the answer be 22.5 or -22.5?

The answer in the back of the book says 22.5 so I'm not sure if I'm missing something or if it's a typo.

2. $\vec{a}\cdot\vec{b}=\|\vec{a}\|\|\vec{b}\|\cos(\al pha)$

3. Originally Posted by IanCarney
In the following question, would the answer be 22.5 or -22.5?

The answer in the back of the book says 22.5 so I'm not sure if I'm missing something or if it's a typo.
The answer is correct. Notice that the vectors are not lined up tail to tail. What did you try and what did you get.

4. Originally Posted by TheEmptySet
The answer is correct. Notice that the vectors are not lined up tail to tail. What did you try and what did you get.
Ah, I see. Thanks, I get it now.