Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Application of Integrals

Question:

A student observes an open-air honeybee nest on the branch of a tree, whose plane figure is parabolic shape given by $x^2 = 4y$. Then the area (in square units) of the region bounded by parabola $x^2 = 4y$ and the line $y = 4$ is:

Options:

$\frac{32}{3}$

$\frac{64}{3}$

$\frac{128}{3}$

$\frac{256}{3}$

Correct Answer:

$\frac{64}{3}$

Explanation:

The correct answer is Option (2) → $\frac{64}{3}$

The required region is symmetric about the y-axis.

So, required area (in sq. units) is:

$= 2 \int\limits_{0}^{4} x \, dy = 2 \int\limits_{0}^{4} 2\sqrt{y} \, dy = 4 \left[ \frac{y^{\frac{3}{2}}}{\frac{3}{2}} \right]_{0}^{4} = \frac{64}{3}$