Vectors dot prodoct question/clarification

**IanCarney** · May 22nd 2011, 10:38 AM

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.

**Plato** · May 22nd 2011, 10:47 AM

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

**TheEmptySet** · May 22nd 2011, 10:49 AM

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.

**IanCarney** · May 22nd 2011, 11:05 AM

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.

Thread: Vectors dot prodoct question/clarification