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JEE Advanced 2024Paper 1
Exam
JEE Advanced
Year
2024
Paper
Paper 1
Subject
Mathematics
Chapter
Vector Algebra

JEE Advanced 2024 · Paper 1 · Mathematics · Vector Algebra

Let O P =(α-1)/(α) i + j + k , O Q = i +(β-1)/(β) j + k and O R = i...

Let OP→=α−1αi^+j^+k^,OQ→=i^+β−1βj^+k^\overrightarrow{O P}=\frac{\alpha-1}{\alpha} \hat{i}+\hat{j}+\hat{k}, \overrightarrow{O Q}=\hat{i}+\frac{\beta-1}{\beta} \hat{j}+\hat{k} and OR→=i^+j^+12k^\overrightarrow{O R}=\hat{i}+\hat{j}+\frac{1}{2} \hat{k} be three vectors, where α,β∈R−{0}\alpha, \beta \in \mathbb{R}-\{0\} and OO denotes the origin. If (OP→×OQ→)⋅OR→=0(\overrightarrow{O P} \times \overrightarrow{O Q}) \cdot \overrightarrow{O R}=0 and the point (α,β,2)(\alpha, \beta, 2) lies on the plane 3x+3y−z+l=03 x+3 y-z+l=0, then the value of ll is ____

Correct answer

0

Step-by-step solution

(\overrightarrow{\mathrm{OP}} \times \overrightarrow{\mathrm{OQ}}) \cdot \overrightarrow{\mathrm{OR}}=0 \left|α−1α111β−1β11112\begin{array}{ccc}\frac{\alpha-1}{\alpha} & 1 & 1 \\ 1 & \frac{\beta-1}{\beta} & 1 \\ 1 & 1 & \frac{1}{2}\end{array}\right|=0 \alpha+\beta+1=0...(1) Also (α,β,2)\quad(\alpha, \beta, 2) lies on 3x+3y−z+l=0⇒3α+3β−2+l=0⇒l=2−3(α+β)3 \mathrm{x}+3 \mathrm{y}-\mathrm{z}+l=0 \Rightarrow \quad 3 \alpha+3 \beta-2+l=0 \quad \Rightarrow \quad l=2-3(\alpha+\beta) ...(2) use (1) in (2) ⇒l=5\Rightarrow l=5
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