Question

Use the Law of Cosines to find the angle α between the vectors. (Assume 0^o ≤ α ≤ 180^o.)

v = i + j,   w = 2i - 2j

Answer 1

Step 1:

The vectors are and

The vectors end points are .

Calculate the length of the three sides.

Step 2:

Use Cosine rule, .

 

 

Solution:

.