I am trying to teach myself AS maths. This is from Introducing mechanics a txt book by Jefferson and Beadsworth. exercise 2C question 1 part vi) Question given vector b=6i-3j-2k; |b| is established as = 7 by calculation Question Calculate the angles between b and positive x-, y- and z- directions. My answer: these are sine alpha =6/7 = 59 degrees - subtract from 180 to give angle from z axis Sine beta =2/7 = 16.6 degrees - this is angle from x axis Sine theta = 3/7 = 25.4 degrees. Need to add 90 degrees to give angle from y axis. However these are not the correct answers. The correct answers appear to be cosines of the above. This does not make sense to me can you expalin?