Medium MCQ +4 / -1 PYQ · JEE Mains 2023

The shortest distance between the lines $x+1=2y=-12z$ and $x=y+2=6z-6$ is :

  1. A 3
  2. B $\frac{5}{2}$
  3. C $\frac{3}{2}$
  4. D 2 Correct answer

Solution

$L_{1}: \frac{x+1}{1}=\frac{y}{\frac{1}{2}}=\frac{z}{\frac{-1}{12}}$ <br/><br/> $$ \begin{aligned} & L_{2}: \frac{x}{1}=\frac{y+2}{1}=\frac{z-1}{\frac{1}{6}} \\\\ & \text { S.D }=\left|\frac{(-\hat{i}+2 \hat{j}-\hat{k}) \cdot(2 \hat{i}-3 \hat{j}+6 \hat{k})}{7}\right| \\\\ & =\left|\frac{-2-6-6}{7}\right|=2 \text { units } \end{aligned} $$

About this question

Subject: Mathematics · Chapter: Three Dimensional Geometry · Topic: Direction Cosines and Ratios

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