Mathematics · Hyperbola

JEE Main 2026 — 21 January, Morning Shift — Question 11

Let the foci of hyperbola coincide with the foci of the ellipse x236+y216=1\frac{x^{2}}{36}+\frac{y^{2}}{16}=1. If the eccentricity of the hyperbola is 5 , then the length of its latus rectum is:

  1. Option A:

    1212

  2. Option B:

    1616

  3. Option C:

    965\frac{96}{\sqrt{5}}

    Correct
  4. Option D:

    24524 \sqrt{5}

Answer: C

Step-by-step solution

Let e1\mathrm{e}_{1} be eccentricity of ellipse ⇒e1=1−1636=1−49=53\Rightarrow e_{1}=\sqrt{1-\frac{16}{36}}=\sqrt{1-\frac{4}{9}}=\frac{\sqrt{5}}{3}

So ae1=6⋅53=25\mathrm{ae}_{1}=6 \cdot \frac{\sqrt{5}}{3}=2 \sqrt{5}

Now H : x2p2−y2q2=1\frac{x^{2}}{p^{2}}-\frac{y^{2}}{q^{2}}=1

pe=ae1pe=\mathrm{ae}_{1}

p.5=25p.5=2 \sqrt{5}

p=25\mathrm{p}=\frac{2}{\sqrt{5}} ⇒e2=1+q2p2\Rightarrow \mathrm{e}^{2}=1+\frac{\mathrm{q}^{2}}{\mathrm{p}^{2}}

⇒25=1+5q24\Rightarrow 25=1+\frac{5 \mathrm{q}^{2}}{4}

⇒q2=965\Rightarrow \mathrm{q}^{2}=\frac{96}{5}

So length of LR=2q2p=965L R= \frac{2 q^{2}}{p}=\frac{96}{\sqrt{5}}

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
Hyperbola
Topic
Introduction to Hyperbola