The area (in sq. units) of the region (x, y): 0 ≤ y ≤ 2|x| + 1, 0 ≤ y ≤ x² + 1, |x| ≤ 3 is

Solution & Explanation

Related Formula

Area under a curve using definite integration bounded by curves:

Area = 2 ∫ₐ^b f(x) dx
Core Logic

Since both bounding graphs are symmetric about the y-axis, we can integrate over the positive domain (x ≥ 0) and double the result:

Area Bounded by Curves and Absolute Value Functions diagram for Q70 - JEE Main 2025 Morning
Area Bounded by Curves and Absolute Value Functions diagram for Q70 - JEE Main 2025 Morning
Intersecting points: x² + 1 = 2x + 1 x = 2.

Step 1: Setting Up the Bound Segments

The region splits into two integral segments based on which curve sits lower: Segment 1: From 0 to 2, bounded by the parabola y = x² + 1. Segment 2: From 2 to 3, bounded by the straight line y = 2x + 1.

Step 2: Performing Integration
$Area = 2 [ ∫₀² (x² + 1) dx + ∫₂³ (2x + 1) dx ]= 2 [ ( (8)/(3) + 2 ) + (9 + 3 - 4 - 2) ] = 2 [ (14)/(3) + 6 ] = (64)/(3)$
Pattern Recognition

Exploiting structural symmetry drops the integration limits, avoiding messy sign evaluations with absolute terms.

Chapter Mix

Class 12 Maths: Area Under Curves

More Area Under Curves Previous-Year Questions — Page 4

Q67 jee_main_2025_24_jan_evening Area Under Curves
The area of the region enclosed by the curves y=ex, y=|ex-1| and y-axis is:
  • A. 1+ ₑ2
  • B. ₑ2
  • C. 2 ₑ2-1
  • D. 1- ₑ2

Solution

Related Formula

The area between two curves y₁(x) and y₂(x) from x = a to x = b is given by:

Area = ∫ₐb |y₁(x) - y₂(x)| dx
Core Logic

Analyze the curves to locate intersection points :

  • Curve 1: y = e^x
  • Curve 2: y = |e^x - 1|
  • Boundary: y-axis (x = 0)
  • For x < 0, e^x < 1 ⇒ |e^x - 1| = 1 - e^x .

    Find intersection: e^x = 1 - e^x ⇒ 2e^x = 1 ⇒ e^x = (1)/(2) ⇒ x = -ln 2.

    Area bounded by exponential curves diagram for Q67 - JEE Main 2025 Evening
    Area bounded by exponential curves diagram for Q67 - JEE Main 2025 Evening

Step 1: Set up the Definite Integral

The integration spans from x = -ln 2 to x = 0. In this interval, e^x ≥ 1 - e^x:

Area = ∫-ln 2⁰ [ e^x - (1 - e^x) ] dx Area = ∫-ln 2⁰ (2e^x - 1) dx
Step 2: Integration Evaluation

Integrate term-by-term :

Area = [ 2e^x - x ]-ln 2⁰ = (2e⁰ - 0) - (2e-ln 2 - (-ln 2)) = 2 - (2((1)/(2)) + ln 2) = 2 - (1 + ln 2) = 1 - ln 2
Pattern Recognition

Modulus graphs split at their critical point (e^x = 1 ⇒ x = 0). Recognizing that the required segment lies strictly in the negative quadrant simplifies the definition of the upper and lower functions immediately.

Chapter Mix

Class 12 Mathematics: Application of Integrals

Q63 jee_main_2025_24_jan_morning Area Bounded by Multiple Curves
The area of the region (x,y) x² + 4x + 2 ≤ y ≤ |x + 2| is equal to :
  • A. 7
  • B. 24/5
  • C. 20/3
  • D. 5

Solution

Related Formula

The net area between two intersecting functions y₂(x) and y₁(x) from lower limit a to upper limit b is evaluated using the definite integral:

Area = ∫ₐb [y₂(x) - y₁(x)] dx
Core Logic

Let's perform a horizontal shift transformation by defining X = x + 2 to simplify the expressions:

  • Parabola: y = x² + 4x + 2 = (x+2)² - 2 y = X² - 2
  • Absolute curve: y = |x + 2| y = |X|
  • This coordinate translation preserves area completely while shifting the axis to the origin.

Step 1: Compute Points of Intersection

Find where the transformed curves intersect by equating the functions: |X|² - 2 = |X|

|X|² - |X| - 2 = 0 (|X| - 2)(|X| + 1) = 0

Since |X| ≥ 0, we discard |X| = -1. This gives |X| = 2 X = ± 2.

Step 2: Set up and Evaluate the Transformed Integral

Since both curves are symmetric about the vertical line X = 0, we can compute the area for the positive half and double it:

Area = 2 ∫₀² [ X - (X² - 2) ] dX = 2 ∫₀² ( 2 + X - X² ) dX

Integrate the polynomial row-by-row:

= 2 [ 2X + (X²)/(2) - (X³)/(3) ]₀² = 2 [ 2(2) + (4)/(2) - (8)/(3) ] = 2 [ 4 + 2 - (8)/(3) ] = 2 [ 6 - (8)/(3) ] = 2 · (10)/(3) = (20)/(3)
Pattern Recognition

Applying a horizontal variable substitution matching X = x + ± c shifts complex quadratic forms to centered formats, which avoids tedious arithmetic across asymmetrical integration limits.

Chapter Mix

Class 12 Mathematics: Application of Integrals

Q jee_main_2025_28_jan_evening Area Bounded by Algebraic and Rational Curves
The area of the region bounded by the curves x(1+y²)=1 and y²=2x is :
  • A. 2((π)/(2)-(1)/(3))
  • B. (π)/(4)-(1)/(3)
  • C. (π)/(2)-(1)/(3)
  • D. (1)/(2)((π)/(2)-(1)/(3))

Solution

Related Formula

Area integrating with respect to y:

A = ∫y₁y₂ (xright - xleft) dy

Standard integral:

∫ (1)/(1+y²) dy = ⁻¹(y)
Core Logic

The boundary curves are:

  • x = (1)/(1+y²)
  • x = (y²)/(2)
  • Find intersection points by setting x equal:

(1)/(1+y²) = (y²)/(2) 2 = y²(1+y²) y⁴ + y² - 2 = 0 (y² + 2)(y² - 1) = 0

Since y is real, y² = 1 y = ± 1. When y = ± 1, x = (1)/(2). Intersection points are ((1)/(2), 1) and ((1)/(2), -1).

Step 1: Set up and Compute Area Integral

Between y = -1 and y = 1, (1)/(1+y²) ≥ (y²)/(2).

Area = ∫₋₁¹ ( (1)/(1+y²) - (y²)/(2) ) dy

Since the integrand is an even function of y:

Area = 2 ∫₀¹ ( (1)/(1+y²) - (y²)/(2) ) dy Area = 2 [ ⁻¹(y) - (y³)/(6) ]₀¹ Area = 2 [ ⁻¹(1) - (1)/(6) - (0) ] = 2 ( (π)/(4) - (1)/(6) ) = (π)/(2) - (1)/(3)
Pattern Recognition

Whenever curves are functions of y², integrating along the y-axis avoids dealing with messy radical functions (square roots) and naturally accounts for symmetry across the x-axis.

Chapter Mix

Class 12 Mathematics: Application of Integrals

Q57 jee_main_2025_29_jan_morning Area Under Curves
Let the area of the region (x, y) : 2y ≤ x² + 3 , y + |x| ≤ 3 , y ≥ |x - 1| be A. Then 6A is equal to:
  • A. 16
  • B. 12
  • C. 18
  • D. 14

Solution

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

Plotting the boundary lines and tracking intersection points yields a composite geometric region bounding a central area.

Area Under Curves diagram for Q57 - JEE Main 2025 Morning
Area Under Curves diagram for Q57 - JEE Main 2025 Morning

Step 1: Set up the integral pieces

The bounded region A can be conceptualized as a total bounding box/rectangle minus specific external integrals:

A = 4 - 2 ∫₀¹ [ (3 - x) - ( (x² + 3)/(2) ) ] dx
Step 2: Evaluate the Integral
A = 4 - 2 [ 3x - (x²)/(2) - (x³)/(6) - (3)/(2)x ]₀¹ A = 4 - 2 [ 3 - (1)/(2) - (1)/(6) - (3)/(2) ] = 4 - 2 [ (5)/(6) ] = 4 - (5)/(3) = (7)/(3)
Step 3: Calculate 6A

6A = 6 × (7)/(3) = 14

Pattern Recognition

When dealing with multiple absolute functions (|x|, |x-1|), check for coordinate mirror symmetry across vertical axes to slash total required calculus computations in half.

Chapter Mix

Class 12 Mathematics: Application of Integrals

Q jee_main_2024_01_february_morning Area Between Curves
The area enclosed by the curves xy+4y=16 and x+y=6 is equal to:
  • A. 28-30 ₑ2
  • B. 30-28 ₑ2
  • C. 30-32 ₑ2
  • D. 32-30 ₑ2

Solution

Related Formula

Area enclosed between two intersecting curves y₁ = f(x) and y₂ = g(x) from boundary limits x = a to x = b:

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

Given the two boundary curves:

  • xy + 4y = 16 y(x+4) = 16 y = (16)/(x+4)
  • x + y = 6 y = 6 - x
  • Find the intersection points by equating the two expressions for y:

(16)/(x+4) = 6 - x 16 = (6-x)(x+4) 16 = 6x + 24 - x² - 4x x² - 2x - 8 = 0 (x-4)(x+2) = 0 x = 4, x = -2
Step 1: Integral Formulation

Between x = -2 and x = 4, the line y = 6 - x lies above the curve y = (16)/(x+4). Therefore, the required enclosed area is:

Area = ∫₋₂⁴ ( (6-x) - (16)/(x+4) ) dx Area = [ 6x - (x²)/(2) - 16 ln|x+4| ]₋₂⁴

Area Between Curves diagram for Q10 - JEE Main 2024 01 February Morning
The diagram displays the shaded region enclosed between the straight line and the hyperbola between limits minus two and four.

Step 2: Apply Limits and Simplify

Substitute the upper limit x = 4:

U = 6(4) - (4²)/(2) - 16 ln|4+4| = 24 - 8 - 16 ln 8 = 16 - 16 ln 8

Substitute the lower limit x = -2:

L = 6(-2) - ((-2)²)/(2) - 16 ln|-2+4| = -12 - 2 - 16 ln 2 = -14 - 16 ln 2

Subtract the lower limit value from the upper limit value:

Area = U - L = (16 - 16 ln 8) - (-14 - 16 ln 2) Area = 30 - 16 ln(2³) + 16 ln 2 = 30 - 48 ln 2 + 16 ln 2 Area = 30 - 32 ln 2 = 30 - 32 ₑ2
Pattern Recognition

Sees: Area bounded by a straight line and a shifting rectangular hyperbola. Shortcut: The roots of the difference equation x² - 2x - 8 = 0 directly give the limits. Always check graph orientations to place the upper linear equation before the curve equation inside the integral bracket to preserve absolute area values.

Chapter Mix

Class 12 Mathematics: Application of Integrals Class 11 Mathematics: Conic Sections (Hyperbola)

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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%)