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Question
The volume of the parallelepiped whose coterminus edges are `7hat"i" + lambdahat"j" - 3hat"k", hat"i" + 2hat"j" - hat"k", -3hat"i" + 7hat"j" + 5hat"k"` is 90 cubic units. Find the value of λ
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Solution
Volume of the parallelepiped = `[bar"a", bar"b", bar"c"]`
`|(7, lambda, -3),(1, 2, -1),(-3, 7, 5)|` = 90
7(10 + 7) – λ(5 – 3) – 3(7 + 6) = 90
7(17) – λ(2) – 3(13) = 90
119 – 2λ – 39 = 90
2λ = 119 – 39 – 90
2λ = – 10
λ = – 5
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