Mathematics · 3D Geometry

JEE Main 2026 — 4 April, Evening Shift — Question 37

The shortest distance between the lines r⃗=(13i^+2j^+83k^)+λ(2i^−5j^+6k^)\vec{r} = \left(\frac{1}{3}\hat{i} +2\hat{j} +\frac{8}{3}\hat{k}\right) + \lambda \left(2\hat{i} -5\hat{j} +6\hat{k}\right) and r⃗=(−23i^−13k^)+μ(j^−k^),λ,μ∈R,\vec{r} = \left(-\frac{2}{3}\hat{i} -\frac{1}{3}\hat{k}\right) + \mu \left(\hat{j} -\hat{k}\right), \lambda , \mu \in \mathbb{R}, is:

  1. Option A:

    5\sqrt{5}

  2. Option B:

    33

    Correct
  3. Option C:

    232\sqrt{3}

  4. Option D:

    15\sqrt{15}

Answer: B

Step-by-step solution

a⃗1=13i^+2j^+83k^\vec{a}_{1}=\frac{1}{3} \hat{i}+2 \hat{j}+\frac{8}{3} \hat{k} a→2=−23i^−13k^\overrightarrow{\mathrm{a}}_{2}=\frac{-2}{3} \hat{\mathrm{i}}-\frac{1}{3} \hat{\mathrm{k}} b→1=2i^−5j^+6k^,b→2=j^−k^\overrightarrow{\mathrm{b}}_{1}=2 \hat{\mathrm{i}}-5 \hat{\mathrm{j}}+6 \hat{\mathrm{k}}, \overrightarrow{\mathrm{b}}_{2}=\hat{\mathrm{j}}-\hat{\mathrm{k}} b→1×b→2=∣i^j^k^2−5601−1∣=−i^+2j^+2k^\overrightarrow{\mathrm{b}}_{1} \times \overrightarrow{\mathrm{b}}_{2}=\left|\begin{array}{ccc}\hat{\mathrm{i}} & \hat{\mathrm{j}} & \hat{\mathrm{k}} 2 & -5 & 6 0 & 1 & -1\end{array}\right|=-\hat{\mathrm{i}}+2 \hat{\mathrm{j}}+2 \hat{\mathrm{k}} a⃗1−a⃗2=i^+2j^+3k^\vec{a}_{1}-\vec{a}_{2}=\hat{i}+2 \hat{j}+3 \hat{k} S.D =∣(a⃗1−a⃗2)⋅(b⃗1×b⃗2)∣b⃗1×b⃗2∣∣=\left|\frac{\left(\vec{a}_{1}-\vec{a}_{2}\right) \cdot\left(\vec{b}_{1} \times \vec{b}_{2}\right)}{\left|\vec{b}_{1} \times \vec{b}_{2}\right|}\right| S.D=∣(i^+2j^+3k^)⋅(−i^+2j^+2k^)3∣S . D=\left|\frac{(\hat{i}+2 \hat{j}+3 \hat{k}) \cdot(-\hat{i}+2 \hat{j}+2 \hat{k})}{3}\right| =93=3=\frac{9}{3}=3

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
3D Geometry
Topic
Skew lines & shortest distance between them