Question:
Let a, b, c be three vectors satisfying
a × b = ( a × c),
| a|=| c|=1, | b|=4 and | b × c|=√(15).
If a · b = ?, then λ equals
Let a, b, c be three vectors satisfying
a × b = ( a × c),
| a|=| c|=1, | b|=4 and | b × c|=√(15).
If a · b = ?, then λ equals
Show Hint
If a × x=0, then x ∥ a.
Updated On: Mar 20, 2026
- \(1\)
- \(-1\)
- \(2\)
- -4
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The Correct Option is B
Solution and Explanation
From a × b = a × c ⟹ a × ( b- c)=0,
so b- c ∥ a.
Using magnitude relations and dot products, the consistent value is
a· b=-1.
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