Mathematics · Area under the Curves

JEE Main 2026 — 28 January, Evening Shift — Question 11

Let P1:y=4x2P_{1}: y=4 x^{2} and P2:y=x2+27P_{2}: y=x^{2}+27 be two parabolas. If the area of the bounded region enclosed between P1P_{1} and P2P_{2} is six times the area of the bounded region enclosed between the line y=αx,α>0\mathrm{y}=\alpha \mathrm{x}, \alpha>0 and P1\mathrm{P}_{1}, then α\alpha is equal to :

  1. Option A:

    8

  2. Option B:

    15

  3. Option C:

    12

    Correct
  4. Option D:

    6

Answer: C

Step-by-step solution

Area bounded between P1P_{1} & P2P_{2} is ∫−33((x2+27)−(4x2))dx\int_{-3}^{3}\left(\left(x^{2}+27\right)-\left(4 x^{2}\right)\right) d x (P.O.I. of P1P_{1} & P2P_{2} is x=±3x= \pm 3 )

=2∫03(27−3x2)dx=2[27x−x3]03=2 \int_{0}^{3}\left(27-3 \mathrm{x}^{2}\right) \mathrm{dx}=2\left[27 \mathrm{x}-\mathrm{x}^{3}\right]_{0}^{3}

=2[81−27]=108=2[81-27]=108

∴ Area bounded between P1\mathrm{P}_{1} & L is 18 sq. units (Area between x2=4x^{2}=4 ay & line x=myx=m y ) is 8a23m3\frac{8 a^{2}}{3 m^{3}}

∴ Area between x2=y4&x=yα\mathrm{x}^{2}=\frac{\mathrm{y}}{4} \& \mathrm{x}=\frac{\mathrm{y}}{\alpha} is 8⋅(116)23⋅(1α)3=18\frac{8 \cdot\left(\frac{1}{16}\right)^{2}}{3 \cdot\left(\frac{1}{\alpha}\right)^{3}}=18

⇒816.163α3=18⇒α3=26.33\Rightarrow \frac{\frac{8}{16.16}}{\frac{3}{\alpha^{3}}}=18 \Rightarrow \alpha^{3}=2^{6} .3^{3}

⇒α=12\Rightarrow \alpha=12

Solution figure

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
Area under the Curves
Topic
Area under the Curves