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Question
Find a unit vector in the opposite direction of `bar("u")`. Where `bar("u") = 8hat"i" + 3hat"j" - hat"k"`
Solution
Required vector = `(-bar("u"))/|bar("u")|`
= `-(8hat"i" + 3hat"j" - "k")/sqrt(64 + 9 + 1)`
= `(-8hat"i" - 3hat"j" + "k")/sqrt(74)`
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