In each of the following, find the angle formed by u and v:

(a) u = [2, 1] and v = [1,−3]
(b) u = [−1, 0, 1] and v = [0, 2,−2]

2 answers

I will do the first, you do the second
u•v = |u||v|cosØ, where Ø is the angle between them
cos Ø = (2 - 3)/(√5√10) = -1/√50 = -..14142
Ø = 81.87°

let me know what you get for the other one.

If you want your angle in radians, make sure your calculator is set to RAD
thanks