SOLUTION: find the vector which is perpendicular to the two vector A=i-3j+2k and B=2i-j+k and is length 5?

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Question 689312: find the vector which is perpendicular to the two vector A=i-3j+2k and B=2i-j+k and is length 5?

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
find the vector which is perpendicular to the two vector A=i-3j+2k and B=2i-j+k and is length 5?
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The cross product is a vector perpendicular.
AxB = V
|i j k|
|1 -3 2|
|2 -1 1|
= i(-3+2) - j(1-4) + k(-1+6)
V = -i + 3j + 5k
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mag(V) = sqrt(1 + 9 + 25) = sqrt(35)
Length 5 V = V*5/sqrt(35) = V*sqrt(35)/7
--> %28-sqrt%2835%29%2F7%29i+%2B+%283sqrt%2835%29%2F7%29j+%2B+%285sqrt%2835%29%2F7%29k
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It's also the negative of the vector above.
%28sqrt%2835%29%2F7%29i+-+%283sqrt%2835%29%2F7%29j+-+%285sqrt%2835%29%2F7%29k