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Question
The value of λ for which the two vectors `2hati - hatj + 2hatk` and `3hati + λhatj + hatk` are perpendicular is ______.
Options
2
4
6
8
Solution
The value of λ for which the two vectors `2hati - hatj + 2hatk` and `3hati + lambdahatj + hatk` are perpendicular is 8.
Explanation:
Dot product of two mutually perpendicular vectors is zero.
`\implies` 2 × 3 + (–1)λ + 2 × 1 = 0
`\implies` λ = 8.
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