Mathematics · 3D Geometry

JEE Main 2024 — 5 April, Shift 1 — Question 1

Let d be the distance of the point of intersection of the lines x+63=y2=z+11\quad \frac{\mathrm{x}+6}{3}=\frac{\mathrm{y}}{2}=\frac{\mathrm{z}+1}{1} \quad and x−74=y−93=z−42\frac{x-7}{4}=\frac{y-9}{3}=\frac{z-4}{2} from the point (7,8,9)(7,8,9). Then d2+6d^{2}+6 is equal to :

  1. Option A:

    72

  2. Option B:

    69

  3. Option C:

    75

    Correct
  4. Option D:

    78

Answer: C

Step-by-step solution

x+63=y2=z+11=λ\frac{\mathrm{x}+6}{3}=\frac{\mathrm{y}}{2}=\frac{\mathrm{z}+1}{1}=\lambda

x=3λ−6,y=2λ,z=λ−1\mathrm{x}=3 \lambda-6, \mathrm{y}=2 \lambda, \mathrm{z}=\lambda-1

x−74=y−93=z−42=μ\frac{x-7}{4}=\frac{y-9}{3}=\frac{z-4}{2}=\mu

x=4μ+7,y=3μ+9,z=2μ+4\mathrm{x}=4 \mu+7, \mathrm{y}=3 \mu+9, \mathrm{z}=2 \mu+4

3λ−6=4μ+7⇒3λ−4μ=133 \lambda-6=4 \mu+7 \Rightarrow 3 \lambda-4 \mu=13 ..(1)

2λ=3μ+9⇒2λ−3μ=92 \lambda=3 \mu+9 \Rightarrow 2 \lambda-3 \mu=9 ..(2)

After solving (1),(2) :

μ=−1\mu=-1 , λ=3\lambda=3

int. point (3,6,2);(7,8,9)(3,6,2) ;(7,8,9)

d2=16+4+49=69\mathrm{d}^{2}=16+4+49=69

d2+6=69+6=75\mathrm{d}^{2}+6=69+6=75

Answer key and solution verified before publishing.

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Exam
JEE Main 2024
Subject
Mathematics
Chapter
3D Geometry
Topic
Intersection of lines, line & plane.
Let d be the distance of the point of intersection of the lines frac… | JEE Main 2024 PYQ with Solution · DhiX AI