JEE Main · Mathematics ↓ Falling

Integral Calculus appeared 62 times across 3 years — 7.2% of Mathematics. This question is from Area Under Curve.

Year 2026 2025 2024 Total
Questions 18 26 18 62

The area of the region enclosed by the parabola (y - 2)² = x - 1 , the line x - 2y + 4 = 0 and the positive coordinate axes is

Numerical Answer Type:
Enter a numerical value Answer: 5 to 5 +4 marks

Solution & Explanation

Related Formula
Area enclosed integrating w.r.t y-axis: ∫ (xright - xleft) dy
Core Logic

Find intersection points between the parabola x = (y-2)² + 1 and the line x = 2y - 4. Set them equal:

(y-2)² + 1 = 2y - 4 y² - 4y + 4 + 1 = 2y - 4 y² - 6y + 9 = 0 ⇒ (y-3)² = 0

The line is tangent to the parabola at y = 3. At y = 3, x = 2(3) - 4 = 2.

We need the area enclosed by the parabola, the line, and the positive coordinate axes. Let's trace the boundary intercepts. The line x = 2y - 4 cuts the y-axis (x=0) at y=2. Parabola vertex is at (1, 2). Parabola cuts y-axis (x=0) at (y-2)² = -1 (No real y-intercept). So the curve (y-2)² = x-1 only exists for x ≥ 1.

Step 1: Setting up the Integral w.r.t y

Area Under Curve diagram for Q29 - JEE Main 2024 Evening
Area Under Curve diagram for Q29 - JEE Main 2024 Evening
Because the area is bound by the positive coordinate axes, we track integration strictly in the first quadrant. The required area is the area between the y-axis, the x-axis, the line, and the curve. Wait, the problem says "area enclosed by the parabola... line... and positive coordinate axes". Let's integrate with respect to y. The boundary curves are x = (y-2)² + 1 (which forms the rightmost boundary) and the axes. The area bounded by the curve with y-axis is from y=0 to y=3 minus the triangular region cut by the line below y=2. The line intersects the x-axis (y=0) at x=-4 and y-axis (x=0) at y=2. The positive coordinate axes enforce boundaries at x ≥ 0, y ≥ 0.

So the exact area is the integral of the parabola's x-value from y=0 to y=3, minus the area of the small triangle outside the region bounded by the line x=2y-4 and the axes in the positive quadrant. The area under the parabola (to the left towards the y-axis) from y=0 to y=3 is ∫₀³ xparabola dy. The line bounds the region on the left from y=2 to y=3. Between y=0 and y=2, the area goes fully to the y-axis. So, area = ∫₀³ xparabola dy - Area of Δ bounded by line and y-axis. The triangle bounded by x=2y-4, x=0, y=2, y=3 is: base is x=2(3)-4 = 2 at y=3, height is 1 (from y=2 to y=3). Triangle area = (1)/(2) × 2 × 1 = 1.

Hence, Enclosed Area = ∫₀³ ((y-2)² + 1) dy - 1.

Step 2: Evaluating the Integral
Area = ∫₀³ (y² - 4y + 5) dy - 1 = [ (y³)/(3) - 2y² + 5y ]₀³ - 1 = ( (27)/(3) - 2(9) + 5(3) ) - 0 - 1 = (9 - 18 + 15) - 1 = 6 - 1 = 5
Pattern Recognition

Instead of evaluating horizontal strips with a broken left-bound, evaluate the total area mapped to the y-axis ∫₀³ x dy and simply subtract the basic geometric triangle removed by the straight line.

Chapter Mix

Class 12 Maths: Integral Calculus

Reference Study Guides

More Integral Calculus Previous-Year Questions — Page 7

Q75 jee_main_2025_03_april_morning Area Under Bounded Curves
The area of the region bounded by the curve y = |x|, x|x - 2|, the x-axis and the lines x = -2 and x = 4 is equal to:
Numerical Answer. Answer: 12 to 12

Solution

Related Formula

Definite integration geometry area: Split boundary zones around intersections where functional dominant switches occur.

Area Under Bounded Curves diagram for Q75 - JEE Main 2025 Morning
Area Under Bounded Curves diagram for Q75 - JEE Main 2025 Morning

Core Logic

Analyze intersection points between y₁ = |x| and y₂ = x|x-2| across required integration span regions:

  • For x in [-2, 0]: |x| = -x and x|x-2| = -x(2-x) = x² - 2x. Max curve tracks through distinct segments.
  • For positive sectors, compute intersections: x = x(2-x) x = 1 or x=0. Also check switch locations where graphs swap dominance.
Step 1: Setting up separate area integral blocks

Using geometric area partitions calculated across continuous regions:

Area = (1)/(2) × 2 × 2 + (1)/(2) × 3 × 3 + (1)/(2) × 1 × 11 = 12

Alternatively, splitting the boundary metrics via continuous definite limits yields identical whole tracking blocks matching exactly to 12 total units.

Pattern Recognition

Plotting multiple curves dynamically highlights dominance shifts quickly. Computing distinct straight triangular chunks saves valuable integration time.

Chapter Mix

Class 12 Mathematics: Integrals (Application of Integrals)

Q68 jee_main_2025_04_april_evening Properties of Definite Integrals
Let f(x) + 2f((1)/(x)) = x² + 5 and 2 g (x) - 3 g ((1)/(2)) = x, x > 0. If α = ∫_ 1 ^ 2 f (x) d x, and β = ∫_ 1 ^ 2 g (x) d x, then the value of 9α + β is:
  • A. 1
  • B. 0
  • C. 10
  • D. 11

Solution

Core Logic

We have two functional equations to solve before integrating.

Equation 1: f(x) + 2f((1)/(x)) = x² + 5 Replace x with (1)/(x):

f((1)/(x)) + 2f(x) = (1)/(x²) + 5

Multiplying this new equation by 2 and subtracting the original Equation 1 eliminates the f((1)/(x)) term:

4f(x) + 2f((1)/(x)) - (f(x) + 2f((1)/(x))) = 2((1)/(x²) + 5) - (x² + 5) 3f(x) = (2)/(x²) - x² + 5 f(x) = (2)/(3x²) - (x²)/(3) + (5)/(3)
Step 1: Finding alpha

Integrate f(x) from 1 to 2:

α = ∫₁² ( (2)/(3x²) - (x²)/(3) + (5)/(3) ) dx = [ -(2)/(3x) - (x³)/(9) + (5x)/(3) ]₁² α = ( -(1)/(3) - (8)/(9) + (10)/(3) ) - ( -(2)/(3) - (1)/(9) + (5)/(3) ) = (19)/(9) - (8)/(9) = (11)/(9)

Thus, 9α = 11.

Step 2: Solving for g(x) and finding beta

We are given 2g(x) - 3g((1)/(2)) = x. Substitute x = (1)/(2):

2g((1)/(2)) - 3g((1)/(2)) = (1)/(2) -g((1)/(2)) = (1)/(2) g((1)/(2)) = -(1)/(2)

Substitute this constant value back into the original equation:

2g(x) - 3(-(1)/(2)) = x 2g(x) + (3)/(2) = x g(x) = (x)/(2) - (3)/(4)

Now find β:

β = ∫₁² ( (x)/(2) - (3)/(4) ) dx = [ (x²)/(4) - (3x)/(4) ]₁² = ( 1 - (3)/(2) ) - ( (1)/(4) - (3)/(4) ) = -(1)/(2) - (-(1)/(2)) = 0
Step 3: Calculating 9alpha + beta

Combining our values:

9α + β = 11 + 0 = 11
Pattern Recognition

Functional equations involving x → (1)/(x) are easily solved by treating the swapped forms as a system of linear equations, allowing direct isolation of the underlying function.

Chapter Mix

Class 12 Mathematics: Definite Integrals Class 12 Mathematics: Functional Equations

Q72 jee_main_2025_04_april_evening Integration by Substitution
If ∫ (√(1 + x²) + x)¹⁰(√(1 + x²) - x)⁹dx = (1)/(m) (( 1 + x ^ 2 + x) ^ n (n 1 + x ^ 2 - x)) + C where C is the constant of integration and m,nin N, then m + n is equal to
Numerical Answer. Answer: 379 to 379

Solution

Core Logic

Let's simplify the integrand by rationalizing the denominator term block. Notice that:

(√(1+x²) - x)(√(1+x²) + x) = (1+x²) - x² = 1 1√(1+x²) - x = √(1+x²) + x

Substituting this back into the denominator expression column:

I = ∫ (√(1+x²) + x)¹⁰ · (√(1+x²) + x)⁹ dx = ∫ (√(1+x²) + x)¹⁹ dx
Step 1: Implementing the Substitution Path

Let t = √(1+x²) + x. Then:

dt = ( x√(1+x²) + 1 ) dx = ( x + √(1+x²)√(1+x²) ) dx = t√(1+x²) dx dx = √(1+x²)t dt

Since √(1+x²) + x = t and √(1+x²) - x = (1)/(t), adding both gives:

2√(1+x²) = t + (1)/(t) √(1+x²) = (1)/(2)(t + (1)/(t))

Thus, dx = (1)/(2t)(t + (1)/(t)) dt = (1)/(2)(1 + (1)/(t²)) dt.

Step 2: Integrating with respect to t

Substitute these back into the integral:

I = ∫ t¹⁹ · (1)/(2)(1 + (1)/(t²)) dt = (1)/(2) ∫ (t¹⁹ + t¹⁷) dt I = (1)/(2) ( t²⁰20 + t¹⁸18 ) + C = t¹⁸4 ( (t²)/(10) + (1)/(9) ) + C = t¹⁸360 (9t² + 10) + C
Step 3: Matching Form and Finding m + n

To match the template format, let's pull out a factor of t:

I = t¹⁹360 ( 9t + (10)/(t) ) + C = t¹⁹360 ( 9(√(1+x²)+x) + 10(√(1+x²)-x) ) + C I = (√(1+x²)+x)¹⁹360 ( 19√(1+x²) - x ) + C

Comparing this directly with the given answer format, we identify:

  • m = 360
  • n = 19
  • Computing m + n:

m + n = 360 + 19 = 379
Pattern Recognition

Expressions containing conjugate factors like √(1+x²) ± x frequently simplify under rationalization because their product equals 1. This dynamic quickly reduces fractional components into single power blocks.

Chapter Mix

Class 12 Mathematics: Indefinite Integrals

Q66 jee_main_2025_04_april_morning Properties of Definite Integrals
The value of ∫₋₁¹ (1 + √(|x| - x))e^x + (√(|x| - x))e-xe^x + e-x dx is equal to
  • A. 3 - 2√(2)3
  • B. 2 + 2√(2)3
  • C. 1 - 2√(2)3
  • D. 1 + 2√(2)3

Solution

Related Formula

King's property of definite integrals:

∫ₐb f(x)dx = ∫ₐb f(a+b-x)dx
Core Logic

Let the given integral be I. Apply King's property by substituting x → -x:

I = ∫₋₁¹ (1 + √(|x| + x))e-x + (√(|x| + x))exe-x + ex dx

Add both integral expressions 2I = I + I:

2I = ∫₋₁¹ (e^x + e-x) + (√(|x| - x) + √(|x| + x))(e^x + e-x)e^x + e-x dx 2I = ∫₋₁¹ (1 + √(|x| - x) + √(|x| + x)) dx
Step 1: Apply Symmetry Properties

The integrand is completely even. Hence, convert intervals:

2I = 2∫₀¹ (1 + √(|x| - x) + √(|x| + x)) dx

For x in [0,1], |x| = x √(|x| - x) = 0 and √(|x| + x) = √(2x):

I = ∫₀¹ (1 + √(2x)) dx
Step 2: Final Integration Execution
I = [ x + √(2) · x3/23/2 ]₀¹ = [ x + 2√(2)3x3/2 ]₀¹ I = 1 + 2√(2)3
Pattern Recognition

When functions involve combinations of exponential components (e^x, e-x) over symmetric boundaries, adding the variable reflection eliminates exponential fractions instantly.

Chapter Mix

Class 12 Mathematics: Definite Integration

Q57 jee_main_2025_07_april_evening Area Under Curves
If the area of the region (x,y):1 + x²≤ y≤ x + 7,11 - 3x is A, then 3A is equal to
  • A. 50
  • B. 49
  • C. 46
  • D. 47

Solution

Related Formula

The area enclosed between upper bounding function yupper and lower function ylower is:

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

We need to find the intersection points of the curves to understand the x+7, 11-3x boundary transition:

  • x+7 = 11-3x 4x = 4 x = 1.
  • Hence, the line switches behavior at x=1.

  • Intersecting 1+x² with x+7:
x² - x - 6 = 0 (x-3)(x+2) = 0 x = -2 or x = 3
  • Intersecting 1+x² with 11-3x:
x² + 3x - 10 = 0 (x+5)(x-2) = 0 x = 2 or x = -5

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

Step 1: Set up Integrals

The transition points show that from x = -2 to 1, the upper line is x+7, and from x = 1 to 2, the upper line is 11-3x.

A = ∫₋₂¹ ((x + 7) - (1 + x²)) dx + ∫₁² ((11 - 3x) - (1 + x²)) dx A = ∫₋₂¹ (x + 6 - x²) dx + ∫₁² (10 - 3x - x²) dx
Step 2: Integration Evaluation

Evaluating the first integral:

[ (x²)/(2) + 6x - (x³)/(3) ]₋₂¹ = ((1)/(2) + 6 - (1)/(3)) - (2 - 12 + (8)/(3)) = (37)/(6) - (-(22)/(3)) = (27)/(2)

Evaluating the second integral:

[ 10x - (3x²)/(2) - (x³)/(3) ]₁² = (20 - 6 - (8)/(3)) - (10 - (3)/(2) - (1)/(3)) = (34)/(3) - (49)/(6) = (19)/(6)

Total Area A:

A = (27)/(2) + (19)/(6) = (81 + 19)/(6) = (100)/(6) = (50)/(3)
Step 3: Calculate 3A

Multiplying the total area by 3:

3A = 3 · ((50)/(3)) = 50
Pattern Recognition

When a boundary contains a or component, always solve for their internal intersection first to identify the exact splitting point of your definite integrals.

Chapter Mix

Class 12 Mathematics: Integral Calculus

More Integral Calculus Questions — jee_main_2024_30_january_evening

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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%)