JEE Main · Mathematics → Steady

Application of Integrals appeared 27 times across 3 years — 3.1% of Mathematics. This question is from Area Under the Curve.

Year 2026 2025 2024 Total
Questions 9 11 7 27

Let the area of the region bounded by the curve y = x, x, lines x = 0, x = (3π)/(2), and the x-axis be A. Then, A + A² is equal to _____.

Numerical Answer Type:
Enter a numerical value Answer: 12 to 12 +4 marks

Solution & Explanation

Core Logic

To evaluate the area under y = x, x, we must identify where one function is greater than the other in [0, (3π)/(2)].

Area Under the Curve diagram for Q22 - JEE Main 2026 Morning
Area Under the Curve diagram for Q22 - JEE Main 2026 Morning
From 0 to (π)/(4): x > x ⇒ y = x From (π)/(4) to (5π)/(4): x > x ⇒ y = x From (5π)/(4) to (3π)/(2): x > x ⇒ y = x

Step 1: Formulate the Area Integral

Since area is bounded by the x-axis, we must take the absolute value if the function goes below the axis. Wait, the function x is negative from π to (5π)/(4), and x is negative from (5π)/(4) to (3π)/(2). Let's integrate carefully:

A = ∫₀π/4 x dx + ∫π/4π x dx + ∫π5π/4 | x| dx + ∫5π/43π/2 | x| dx

Because area is geometric, absolute values are explicitly integrated:

A = ∫₀π/4 x dx + ∫π/4π x dx + ∫π5π/4 (- x) dx + ∫5π/43π/2 (- x) dx
Step 2: Evaluate Integrals
∫₀π/4 x dx = [ x]₀π/4 = 1√(2) - 0 = 1√(2) ∫π/4π x dx = [- x]π/4π = -(-1) - (- 1√(2)) = 1 + 1√(2) ∫π5π/4 (- x) dx = [ x]π5π/4 = - 1√(2) - (-1) = 1 - 1√(2) ∫5π/43π/2 (- x) dx = [- x]5π/43π/2 = -(-1) - ( -(- 1√(2)) ) = 1 - 1√(2)
Step 3: Total Area

Sum the areas together:

A = 1√(2) + (1 + 1√(2)) + (1 - 1√(2)) + (1 - 1√(2)) A = 1√(2) + 1 + 1√(2) + 1 - 1√(2) + 1 - 1√(2) = 3

Now calculate A² + A:

A² + A = (3)² + 3 = 9 + 3 = 12
Pattern Recognition

The expression ( x, x) always splits segments exactly at nπ + π/4. When bounded by the x-axis, parts below y=0 explicitly require negation. Charting the piecewise transitions is non-negotiable.

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_2026_23_january_morning

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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%)