Miss Loi’s mouthful of words from yesterday’s E-Maths vector question covered, as mentioned, almost 75% of the A-Maths Vector syllabus.
The remaining 25%, then, is summarized in the following commandments:
If |u| = 1, u is known as a unit vector. The unit vector in the direction of a given vector a is a/|u|.
With the two simple statements above, unit vectors are forever cast within the exclusive domain of the A-Maths Vectors Club, thus depriving the relieved masses of E-Maths students from ever needing to waste a single brain cell on a question like this:
The vector 
has magnitude 85 and is in the opposite direction of . Express as a column vector. The vector is . Obtain the unit vector in the direction of .
has magnitude 85 and is in the opposite direction of 
. Express as a column vector. The vector 
is 
. Obtain the unit vector in the direction of 
.IMPORTANT: To avert a tragedy, always double-check the order of the letters in the vectors and don’t drive in the wrong direction against the traffic!
