The question:
Given the vectors p = (1 1 -1) and q = (2 1 -1), find the cosine between p and q.
My attempt:
I found the magnitude of p and q, which are and respectively.
I then found the dot product of the vectors, which resulted in 4.
Using I rearranged the equation to:
Substituting the values I got
The answer in the text is
What am I doing wrong? Thanks!