# How do you find the angle between the vectors #u=2i-j# and #v=i-2j#?

##### 2 Answers

Please see the explanation for a description of the process.

#### Explanation:

Compute the dot-product by multiplying the

A second way to compute the dot-product uses the magnitude of the two vectors and the cosine of the angle between the two vectors:

We know that the dot-product is 4, therefore, we need to compute the magnitude of the two vectors and then solve for the angle between,

Substitute into equation [1] and then solve for

The angle is

#### Explanation:

The angle between two vectors is given by the dot product definition.

where

so,

The dot product is

The modulus of

The modulus of

So,