# If #A = <3 ,-1 ,5 >#, #B = <5 ,2 ,8 ># and #C=A-B#, what is the angle between A and C?

##### 1 Answer

Jan 24, 2017

The angle is

#### Explanation:

Let's start by calculating

The angle between

Where

The dot product is

The modulus of

The modulus of

So,