JEE Main · Mathematics → Steady

Application of Integrals appeared 27 times across 3 years — 3.1% of Mathematics. This question is from Area under Curves.

Year 2026 2025 2024 Total
Questions 9 11 7 27

The area (in square units) of the region bounded by the parabola y² = 4(x - 2) and the line y = 2x - 8

Solution & Explanation

Related Formula
Area = ∫y₁y₂ (xR - xL) dy
Core Logic

Area under Curves diagram for Q8 - JEE Main 2024 Morning
Area under Curves diagram for Q8 - JEE Main 2024 Morning

To simplify calculations, shift the origin. Let X = x - 2. The equations become: Parabola: y² = 4X ⇒ X = (y²)/(4) Line: y = 2(X + 2) - 8 ⇒ y = 2X - 4 ⇒ X = (y + 4)/(2)

Step 1: Finding points of intersection

Set the X values equal to find intersection points in terms of y:

(y²)/(4) = (y + 4)/(2)

y² = 2y + 8

y² - 2y - 8 = 0 (y - 4)(y + 2) = 0

The intersection points are at y = -2 and y = 4.

Step 2: Area Integration

Integrate with respect to y from -2 to 4:

A = ∫₋₂⁴ ( xR - xL ) dy A = ∫₋₂⁴ ( (y + 4)/(2) - (y²)/(4) ) dy A = [ (y²)/(4) + 2y - (y³)/(12) ]₋₂⁴

Upper limit (y=4): (16)/(4) + 8 - (64)/(12) = 4 + 8 - (16)/(3) = 12 - (16)/(3) = (20)/(3) Lower limit (y=-2): (4)/(4) - 4 - (-8)/(12) = 1 - 4 + (2)/(3) = -3 + (2)/(3) = -(7)/(3)

A = (20)/(3) - (-(7)/(3)) = (27)/(3) = 9

The solution simplifies it directly to 9 square units.

Pattern Recognition

For a horizontal parabola interacting with a line, integrating along the y-axis is always cleaner than splitting it into multiple integrals along the x-axis.

Chapter Mix

Class 12 Maths: Application of Integrals

Reference Study Guides

More Application of Integrals Previous-Year Questions — Page 6

Q11 jee_main_2024_31_jan_evening Area Under Curves
The area of the region enclosed by the parabola y = 4x - x² and 3y = (x - 4)² is equal to
  • A. (32)/(9)
  • B. 4
  • C. 6
  • D. (14)/(3)

Solution

Related Formula
Area = ∫ₐb (yupper - ylower) dx
Core Logic

Area Under Curves diagram for Q11 - JEE Main 2024 Evening
Area Under Curves diagram for Q11 - JEE Main 2024 Evening

Find intersection points of y = 4x - x² and 3y = (x - 4)²:

3(4x - x²) = x² - 8x + 16 12x - 3x² = x² - 8x + 16 4x² - 20x + 16 = 0 x² - 5x + 4 = 0

Roots are x = 1, 4.

Area integral:

Area = ∫₁⁴ [ (4x - x²) - ((x - 4)²)/(3) ] dx = [ (4x²)/(2) - (x³)/(3) - ((x - 4)³)/(9) ]₁⁴ = [ 2(16) - (64)/(3) - 0 ] - [ 2(1) - (1)/(3) - ((-3)³)/(9) ] = ( 32 - (64)/(3) ) - ( 2 - (1)/(3) + 3 ) = (32)/(3) - ( 5 - (1)/(3) ) = (32)/(3) - (14)/(3) = (18)/(3) = 6
Chapter Mix

Class 12 Maths: Applications of the Integrals

Q5 jee_main_2024_31_jan_morning Area 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 is
  • A. (16)/(3)
  • B. (64)/(3)
  • C. (8)/(3)
  • D. (32)/(3)

Solution

Core Logic

Given y² ≤ 4x and x < 4. Analyze the inequality (xy(x-1)(x-2))/((x-3)(x-4)) > 0 considering y > 0 and y < 0 separately.

Area bounded by Parabolas and Inequalities diagram for Q5 - JEE Main 2024 Morning
Area bounded by Parabolas and Inequalities diagram for Q5 - JEE Main 2024 Morning

Step 1: Case I (y > 0)

If y > 0, the inequality reduces to (x(x-1)(x-2))/((x-3)(x-4)) > 0. Using wavy curve method and given x in (0, 4): x in (0, 1) (2, 3).

Step 2: Case II (y < 0)

If y < 0, the inequality reduces to (x(x-1)(x-2))/((x-3)(x-4)) < 0. Using wavy curve method and given x in (0, 4): x in (1, 2) (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).

Chapter Mix

Class 12 Maths: Area Under Curves Class 11 Maths: Linear Inequalities

More Application of Integrals Questions — jee_main_2024_30_jan_morning

Practice all Application of Integrals previous-year questions →

Rankbit System
JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)