AP EAMCET · Maths · Vector Algebra
\(\vec{u}, \vec{v}, \vec{w}\) are three unit vectors. Let \(\vec{p}=\vec{u}+\vec{v}+\vec{w}, \vec{q}\) \(=\vec{u} \times(\vec{v} \times \vec{w})\).If \(\vec{p} \cdot \vec{u}=\frac{3}{2}, \vec{p} \cdot \vec{v}=\frac{7}{4},|\vec{p}|=2\) and \(\vec{v}=\mathrm{K} \vec{q}\), then \(K=\)
- A \(-1\)
- B \(2\)
- C \(3\)
- D \(-2\)
Answer & Solution
Correct Answer
(B) \(2\)
Step-by-step Solution
Detailed explanation
Given that \(|\vec{u}|=|\vec{v}|=|\vec{w}|=1\) \(\therefore \vec{p} \cdot \vec{u}=(\vec{u}+\vec{v}+\vec{w}) \cdot \vec{u}=\frac{3}{2} \Rightarrow|\vec{u}|^2+\vec{u} \cdot \vec{v}+\vec{w} \cdot \vec{u}=\frac{3}{2}\)…
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