JEE Mains · Maths · STD 12 - 10. vector algebra
Let \(\quad \vec{u}=\hat{i}-\hat{j}-2 \hat{k}, \vec{v}=2 \hat{i}+\hat{j}-\hat{k}, \vec{v} \cdot \vec{w}=2 \quad\) and \(\vec{v} \times \vec{w}=\vec{u}+\lambda \vec{v}\). Then \(\vec{u} \cdot \vec{w}\) is equal to \(......\)
- A \(1\)
- B \(\frac{3}{2}\)
- C \(2\)
- D \(-\frac{2}{3}\)
Answer & Solution
Correct Answer
(A) \(1\)
Step-by-step Solution
Detailed explanation
\(\overrightarrow{ u }=(1,-1,-2), \overrightarrow{ v }=(2,1,-1), \overrightarrow{ v } \cdot \overrightarrow{ w }=2\) \(\overrightarrow{ v } \times \overrightarrow{ w }=\overrightarrow{ u }+\lambda \overrightarrow{ v } \ldots \ldots \ldots \ldots \ldots \ldots \ldots(1)\) Taking…
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