Question

Find the angle between the given vectors to the nearest tenth of a degree. u = <8, 4>, v = <9, -9> (5 points)

Answer 1

There are a number of ways to do this. One way is to use a graphics program to measure it.

The angle is 71.6°.

Another way is to divide the vectors and look at the angle of the result.
  (8 +4i)/(9 -9i) = (8 +4i)(9 +9i)/162
  = 36 +108i
So the angle is
  arctan(108/36) ≈ 71.565° ≈ 71.6°