What is the angle between #<8,5,9 ># and #< 4,3,8 >#?
The angle between two vectors depends on the sense of measurement. If
The formula for the angle between any two vectors
Here, # P = < 8, 5, 9 >, Q = < 4, 3, 8 >, P X Q = < 13, -26, 4 >, } P X Q } = sqrt 861, | P | = sqrt 170 and | Q | = sqrt 89.
The angle is
For measurement in the opposite sense, the angle is
Note that anticlockwise rotation for northern latitudes, with respect
to North Pole, is clockwise rotation for the southern latitodes with
respect to the South Pole.