Find the unit vector in the direction of vector 
where P and Q are the points (1, 2, 3) and (4, 5, 6), respectively.
So, 
and 
Now we want to find the 
Now, we have to find the unit direction in the direction of 
.We know that unit vector means that the magnitude of the vector is 1(unit).
It is defined as 
So, we find the magnitude of 
first.
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