MCQMediumJEE 2025Applications of Integrals (Area)

JEE Mathematics 2025 Question with Solution

The area of the region, inside the circle (x23)2+y2=12(x-2\sqrt{3})^2 + y^2 = 12 and outside the parabola y2=23xy^2 = 2\sqrt{3}x is:

  • A

    6π86\pi - 8

  • B

    3π83\pi - 8

  • C

    6π166\pi - 16

  • D

    3π+83\pi + 8

Answer

Correct answer:C

Step-by-step solution

Standard Method

Given: The circle is (x23)2+y2=12(x - 2\sqrt{3})^2 + y^2 = 12 and the parabola is y2=23xy^2 = 2\sqrt{3}x. Find: The area of the region lying inside the circle and outside the parabola.

First, find the points of intersection by substituting y2=23xy^2 = 2\sqrt{3}x into the circle:

(x23)2+23x=12(x - 2\sqrt{3})^2 + 2\sqrt{3}x = 12

Expanding,

x243x+12+23x=12x^2 - 4\sqrt{3}x + 12 + 2\sqrt{3}x = 12 x223x=0x^2 - 2\sqrt{3}x = 0 x(x23)=0x(x - 2\sqrt{3}) = 0

So, the intersection points occur at x=0x = 0 and x=23x = 2\sqrt{3}.

For 0x230 \le x \le 2\sqrt{3}, the upper half of the circle is

y=12(x23)2y = \sqrt{12 - (x - 2\sqrt{3})^2}

and the upper branch of the parabola is

y=23xy = \sqrt{2\sqrt{3}x}

Hence, the required area is

A=023(12(x23)223x)dxA = \int_{0}^{2\sqrt{3}} \left(\sqrt{12 - (x - 2\sqrt{3})^2} - \sqrt{2\sqrt{3}x}\right) dx

From the given solution, this evaluates to

A=6π16A = 6\pi - 16

Therefore, the required area is 6π166\pi - 16. The correct option is C.

Geometry and intersection interpretation

Given: The circle has center (23,0)(2\sqrt{3}, 0) and radius 232\sqrt{3}, and the parabola is y2=23xy^2 = 2\sqrt{3}x. Find: The area common to being inside the circle but outside the parabola.

The circle is centered on the positive xx-axis and the parabola opens to the right. After finding the intersections at x=0x = 0 and x=23x = 2\sqrt{3}, the bounded part of the required region lies between these two curves over the interval [0,23][0, 2\sqrt{3}].

Thus the area is obtained by integrating upper curve minus lower curve over the interval of intersection:

A=023(12(x23)223x)dxA = \int_{0}^{2\sqrt{3}} \left(\sqrt{12 - (x - 2\sqrt{3})^2} - \sqrt{2\sqrt{3}x}\right) dx

the solution concludes that this integral equals

6π166\pi - 16

So the correct option is C.

Common mistakes

  • Using the whole circle area instead of the bounded region between the circle and parabola is incorrect, because the question asks only for the part inside the circle and outside the parabola. Set up the area as the difference of the two curves over the interval of intersection.

  • Finding intersection points incorrectly by solving only one equation or by algebraic expansion errors leads to wrong limits. Substitute y2=23xy^2 = 2\sqrt{3}x into the circle carefully and use the limits x=0x=0 to x=23x=2\sqrt{3}.

  • Subtracting the functions in the wrong order gives a negative area. Over the required interval, take the upper semicircle expression first and then subtract the upper branch of the parabola.

Practice more Applications of Integrals (Area) questions

Get unlimited AI-adaptive practice, mastery tracking, and an AI tutor that explains every step — free to start.

Related questions