Let P₁: y = 4x²$P_{1}: y = 4x^{2}$ and P₂: y = x² + 27$P_{2}: y = x^{2} + 27$ be two parabolas. If the area of the bounded region enclosed between P₁$P_{1}$ and P₂$P_{2}$ is six times the area of the bounded region enclosed between the line y = α x, α > 0$y = \alpha x, \alpha > 0$ and P₁$P_{1}$, then α$\alpha$ is equal to:
A.8$8$
B.15$15$
C.12$12$
D.6$6$
Solution & Explanation
Related Formula
Area enclosed by y = f(x)$y = f(x)$ and y = g(x)$y = g(x)$ from x=a$x=a$ to x=b$x=b$:
Area between P₁$P_1$ and y = α x$y = \alpha x$ is given as 108 / 6 = 18$108 / 6 = 18$ sq. units.
For x² = 4ay$x^2 = 4ay$ and x = my$x = my$, area is (8a²)/(3m³)$\frac{8a^2}{3m^3}$.
Here, the parabola is x² = (y)/(4)$x^2 = \frac{y}{4}$ and line is x = (y)/(α)$x = \frac{y}{\alpha}$.
Thus, 4a = (1)/(4) ⇒ a = (1)/(16)$4a = \frac{1}{4} \Rightarrow a = \frac{1}{16}$, and m = (1)/(α)$m = \frac{1}{\alpha}$.
Using the standard result (8a²)/(3m³)$\frac{8a^2}{3m^3}$ for the area bounded between x²=4ay$x^2=4ay$ and x=my$x=my$ avoids tedious integration for straight lines intersecting parabolas at the origin.
Keywords:#area of the bounded region#JEE Main 2026 Evening Q11#Application of Integrals JEE Main 2026#Area Bounded by Parabolas and Lines JEE Main 2026
More Application of Integrals Previous-Year Questions — Page 6
Q11jee_main_2024_31_jan_eveningArea Under Curves
The area of the region enclosed by the parabola y = 4x - x²$y = 4x - x^2$ and 3y = (x - 4)²$3y = (x - 4)^2$ is equal to
Q5jee_main_2024_31_jan_morningArea bounded by Parabolas and Inequalities
The area of the region (x,y): y² ≤ 4x, x < 4, (xy(x - 1)(x - 2))/((x - 3)(x - 4)) > 0, x ≠ 3$\left\{(x,y): y^2 \le 4x, x < 4, \frac{xy(x - 1)(x - 2)}{(x - 3)(x - 4)} > 0, x \neq 3\right\}$ is
A.(16)/(3)$$\frac{16}{3}$$
B.(64)/(3)$$\frac{64}{3}$$
C.(8)/(3)$$\frac{8}{3}$$
D.(32)/(3)$$\frac{32}{3}$$
Solution
Core Logic
Given y² ≤ 4x$y^2 \le 4x$ and x < 4$x < 4$.
Analyze the inequality (xy(x-1)(x-2))/((x-3)(x-4)) > 0$\frac{xy(x-1)(x-2)}{(x-3)(x-4)} > 0$ considering y > 0$y > 0$ and y < 0$y < 0$ separately.
Area bounded by Parabolas and Inequalities diagram for Q5 - JEE Main 2024 Morning
Step 1: Case I (y > 0)
If y > 0$y > 0$, the inequality reduces to (x(x-1)(x-2))/((x-3)(x-4)) > 0$\frac{x(x-1)(x-2)}{(x-3)(x-4)} > 0$.
Using wavy curve method and given x in (0, 4)$x \in (0, 4)$:
x in (0, 1) (2, 3)$x \in (0, 1) \cup (2, 3)$.
Step 2: Case II (y < 0)
If y < 0$y < 0$, the inequality reduces to (x(x-1)(x-2))/((x-3)(x-4)) < 0$\frac{x(x-1)(x-2)}{(x-3)(x-4)} < 0$.
Using wavy curve method and given x in (0, 4)$x \in (0, 4)$:
x in (1, 2) (3, 4)$x \in (1, 2) \cup (3, 4)$.
Step 3: Area Computation
Because the regions map perfectly without overlap in opposite quadrants relative to the x-axis, they form complete parabolic strips when combined:
Area = 2 ∫₀⁴ √(x) dx = 2 · (2)/(3)[x3/2]₀⁴ = (4)/(3) · 8 = (32)/(3)$= 2 \int_{0}^{4} \sqrt{x} dx = 2 \cdot \frac{2}{3}[x^{3/2}]_{0}^{4} = \frac{4}{3} \cdot 8 = \frac{32}{3}$.
Chapter Mix
Class 12 Maths: Area Under Curves
Class 11 Maths: Linear Inequalities
More Application of Integrals Questions — jee_main_2026_28_january_evening
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