SOLUTION: Find a vector x with ||x||=2 that has the same direction as the vector defined by the points A(3,2,1) and B(1,-1,0). The opposite direction?

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Question 15524: Find a vector x with ||x||=2 that has the same direction as the vector defined by the points A(3,2,1) and B(1,-1,0).
The opposite direction?

Answer by venugopalramana(3286) About Me  (Show Source):
You can put this solution on YOUR website!
Find a vector x with ||x||=2 that has the same direction as the vector defined by the points A(3,2,1) and B(1,-1,0).
The opposite direction?
direction of ab = i(1-3)+j(-1-2)+k(0-1) = -2i-3j-k
vector x has sime direction .Hence vector|x|= s*(-2i-3j-k) where s is a scalar to be found ||x|| = s*||(-2i-3j-k)||=s*sqrt%28%28-2%29%5E2%2B%28-3%29%5E2%2B%28-1%29%5E2%29
s*sqrt%284%2B9%2B1%29=s*sqrt14= 2...given
Hence s = (2/*sqrt14)
vector |x| = (2/*sqrt14)*(-2i-3j-k) ....answer
if the direction is opposite then vector |x| = (2/*sqrt14)*(2i+3j+k)