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JEE Main 202325 JanuaryMorning Shift
Exam
JEE Main
Year
2023
Date
25 January
Shift
Morning Shift
Subject
Mathematics
Chapter
Three Dimensional Geometry

JEE Main 2023 · 25 January · Morning Shift · Mathematics · Three Dimensional Geometry

Consider the lines L _ 1 and L _ 2 given by L _ 1 : (x - 1)/(2) =...

Consider the lines L1{L}_{1} and L2{L}_{2} given by

L1:x−12=y−31=z−22{L}_{1}: \dfrac{x - 1}{2} = \dfrac{y - 3}{1} = \dfrac{z - 2}{2}

L2:x−21=y−22=z−33{L}_{2}: \dfrac{x - 2}{1} = \dfrac{y - 2}{2} = \dfrac{z - 3}{3}

A line L3{L}_{3} having direction ratios 1,−1,−21, - 1, - 2, intersects L1{L}_{1} and L2{L}_{2} at the points PP and QQ respectively. Then the length of line segment PQPQ is

Options

  1. A262\sqrt{6}
  2. B323\sqrt{2}
  3. C434\sqrt{3}
  4. D44

Correct answer

A. 262\sqrt{6}

Step-by-step solution

Given,

The lines L1and{L}_{1} and{L}_{2}givenby</p><p>given by</p><p>{L}_{1}: \dfrac{x - 1}{2} = \dfrac{y - 3}{1} = \dfrac{z - 2}{2}</p><p></p><p>{L}_{2}: \dfrac{x - 2}{1} = \dfrac{y - 2}{2} = \dfrac{z - 3}{3}</p><p>Nowanypointonline</p><p>Now any point on line{L}_{1}isgivenby,</p><p>is given by,</p><p>P = \left(2\lambda + 1, \lambda + 3, 2\lambda + 2\right)</p><p>Andanypointonline</p><p>And any point on line{L}_{2}isgivenby,</p><p>is given by,</p><p>Q = \left(\mu + 2, 2\mu + 2, 3\mu + 3\right)</p><p>Nowequationofline</p><p>Now equation of line{L}_{3}whichpassesthroughwhich passes throughQisgivenby,</p><p>is given by,</p><p>\dfrac{x - \left(\mu + 1\right)}{1} = \dfrac{y - \left(2\mu + 2\right)}{- 1} = \dfrac{z - \left(3\mu + 3\right)}{- 2}</p><p>Nowitalsopassesthrough</p><p>Now it also passes throughP,soweget,</p><p>, so we get,</p><p>⇒ \dfrac{2\lambda - \mu - 1}{1} = \dfrac{\lambda - 2\mu + 1}{- 1} = \dfrac{2\lambda - 3\mu - 1}{- 2}</p><p>Nowonsolvingaboveequationsweget,</p><p>Now on solving above equations we get,\lambda = \mu = 3</p><p>Hence,</p><p>Hence,P(7,6,8)P\left(7, 6, 8\right) and Q(5,8,12)Q\left(5, 8, 12\right)

So, the distance PQ=26PQ = 2\sqrt{6}

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