# If #A = <2 ,4 ,-1 >#, #B = <-1 ,8 ,-5 ># and #C=A-B#, what is the angle between A and C?

##### 1 Answer

Mar 3, 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,