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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 9

Q jee_main_2025_28_jan_evening Integration by Parts
Let f: Rarrow R be a twice differentiable function such that f(2)=1. If F(x)=xf(x) for all xin R, ∫₀²xF(x)dx=6 and ∫₀²x²F(x)dx=40, then F(2)+∫₀²F(x)dx is equal to:
  • A. 11
  • B. 15
  • C. 6
  • D. 13

Solution

Related Formula

Integration by Parts formula:

∫ u · v dx = u ∫ v dx - ∫ ( u' ∫ v dx ) dx
Core Logic

Given F(x) = xf(x) and f(2) = 1 F(2) = 2f(2) = 2.

Let's apply Integration by Parts to the first given integral:

∫₀² x F'(x) dx = 6 [ xF(x) ]₀² - ∫₀² F(x) dx = 6 2F(2) - 0 - ∫₀² F(x) dx = 6 2(2) - ∫₀² F(x) dx = 6 ∫₀² F(x) dx = 4 - 6 = -2
Step 1: Simplify Second Integral via Integration by Parts

Now look at the second integral:

∫₀² x² F''(x) dx = 40

Applying Integration by parts (taking u = x² and v = F''(x)):

[ x² F'(x) ]₀² - ∫₀² 2x F'(x) dx = 40 4 F'(2) - 0 - 2 ∫₀² x F'(x) dx = 40

We already know ∫₀² x F'(x) dx = 6:

4 F'(2) - 2(6) = 40 4 F'(2) - 12 = 40 4 F'(2) = 52 F'(2) = 13
Step 2: Sum the Values

We need to find F'(2) + ∫₀² F(x) dx: 13 + (-2) = 11

Pattern Recognition

Notice how the definition of f(x) is mostly a distraction to find F(2)=2. The problem is fundamentally testing consecutive applications of integration by parts to reduction structures.

Chapter Mix

Class 12 Mathematics: Definite Integration

Q57 jee_main_2025_28_jan_evening Leibnitz Rule and Definite Integral
Let f be a real valued continuous function defined on the positive real axis such that g(x)=∫₀xtf(t)dt. If g(x³)=x⁶+x⁷ then value of Σr=1¹⁵f(r³) is:
  • A. 320
  • B. 340
  • C. 270
  • D. 310

Solution

Related Formula

Newton-Leibnitz Theorem for differentiation under integral sign:

(d)/(dx) ( ∫₀x tf(t) dt ) = xf(x)
Core Logic

Given:

g(x) = ∫₀x tf(t) dt

Differentiating both sides with respect to x:

g'(x) = xf(x) f(x) = (g'(x))/(x)

We are given g(x³) = x⁶ + x⁷. Let y = x³ x = y1/3. Substituting this into the expression for g:

g(y) = (y1/3)⁶ + (y1/3)⁷ = y² + y7/3

Thus, replacing y back with x:

g(x) = x² + x7/3
Step 1: Differentiate g(x) to find f(x)
g'(x) = 2x + (7)/(3)x4/3

Now find f(x):

f(x) = (g'(x))/(x) = 2x + (7)/(3)x4/3x = 2 + (7)/(3)x1/3
Step 2: Evaluate the Summation

We need to find Σr=1¹⁵ f(r³):

f(r³) = 2 + (7)/(3)(r³)1/3 = 2 + (7)/(3)r

Now, compute the summation from r=1 to 15:

Σr=1¹⁵ f(r³) = Σr=1¹⁵ ( 2 + (7)/(3)r ) = Σr=1¹⁵ 2 + (7)/(3)Σr=1¹⁵ r (2 × 15) + (7)/(3) × (15 × 16)/(2) 30 + (7)/(3) × 120 = 30 + 7 × 40 = 30 + 280 = 310
Pattern Recognition

Converting g(x³) directly into a function of variable y=x³ prevents multi-layer chain rule complications when applying differentiation immediately.

Chapter Mix

Class 11 Mathematics: Sequences and Series Class 12 Mathematics: Definite Integration

Q66 jee_main_2025_29_jan_morning Integration by Substitution
The integral 80∫₀(π)/(4)(( θ + θ)/(9 + 16 2θ))dθ is equal to:
  • A. 3 ₑ4
  • B. 6 ₑ₄
  • C. 4 ₑ₃
  • D. 2 ₑ3

Solution

Related Formula
∫ (dt)/(a² - b² t²) = (1)/(2a) ln | (a+bt)/(a-bt) | 2θ = 1 - ( θ - θ)²
Core Logic

Let θ - θ = t. Then ( θ + θ)dθ = dt. Transform limits: When θ = 0 t = 0 - 1 = -1 When θ = (π)/(4) t = 1√(2) - 1√(2) = 0

Step 1: Perform the algebraic substitution

Express the denominator base:

9 + 16 2θ = 9 + 16[1 - t²] = 25 - 16t²

The integral transforms to:

I = 80 ∫₋₁⁰ (dt)/(25 - 16t²) = (80)/(16) ∫₋₁⁰ (dt)/(((5)/(4))² - t²)
Step 2: Execute Integral Calculation
I = 5 [ (1)/(2((5)/(4))) ln | ((5)/(4) + t)/((5)/(4) - t) | ]₋₁⁰ I = 2 [ ln(1) - ln( (1/4)/(9/4) ) ] = 2 [ 0 - ln((1)/(9)) ] = 2ln(9) = 4ln(3)
Pattern Recognition

Whenever ( θ + θ) sits inside the numerator, instantly choose t = θ - θ as your core linear substitution engine to clean denominators.

Chapter Mix

Class 12 Mathematics: Definite Integrals

Q71 jee_main_2025_29_jan_morning Functional Equations with Integrals
Let f: (0, ∞) → R be a twice differentiable function. If for some a ≠ 0 , ∫₀¹ f(λ x) dλ = a f(x) , f(1) = 1 and f(16) = (1)/(8) , then 16 - f'((1)/(16)) is equal to
Numerical Answer. Answer: 112

Solution

Related Formula
Leibniz Integral Rule for differentiation: (d)/(dx)∫₀x f(t) dt = f(x)
Core Logic

Perform variable substitution inside the integral: let λ x = t dλ = (1)/(x) dt. When λ = 0 t = 0; when λ = 1 t = x. The equation transforms to:

(1)/(x) ∫₀x f(t) dt = a f(x) ∫₀x f(t) dt = a x f(x)
Step 1: Differentiate with respect to x

Using Leibniz rule and product rule:

f(x) = a [x f'(x) + f(x)] (1 - a)f(x) = a x f'(x) (f'(x))/(f(x)) = (1-a)/(a) (1)/(x)

Integrating both sides yields:

ln f(x) = ((1-a)/(a))ln x + c f(x) = C x(1-a)/(a)
Step 2: Calculate Constants using boundaries

Given f(1) = 1 C = 1. Given f(16) = (1)/(8) (1)/(8) = (16)(1-a)/(a) 2⁻³ = (2⁴)(1-a)/(a)

-3 = (4(1-a))/(a) -3a = 4 - 4a a = 4

Therefore, power exponent = (1-4)/(4) = -(3)/(4) f(x) = x-(3)/(4).

Step 3: Evaluate target derivative value

Find the derivative:

f'(x) = -(3)/(4) x-(7)/(4)

Substitute x = (1)/(16):

f'((1)/(16)) = -(3)/(4) (2⁻⁴)-(7)/(4) = -(3)/(4) (2⁷) = -(3)/(4) × 128 = -96

Final requested computation calculation:

16 - f'((1)/(16)) = 16 - (-96) = 112
Pattern Recognition

Scaling inputs inside functional definite integrals tracks closely to homogenous Euler equation properties. Converting integrations quickly to local power functions reduces processing parameters.

Chapter Mix

Class 12 Mathematics: Definite Integrals Class 12 Mathematics: Differential Equations

Q2 jee_main_2024_01_february_morning Properties of Definite Integrals
The value of the integral ∫₀(π)/(4) x dx ⁴(2x)+ ⁴(2x) equals:
  • A. √(2)π²8
  • B. √(2)π²16
  • C. √(2)π²32
  • D. √(2)π²64

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:

I = ∫₀(π)/(4) x dx ⁴(2x)+ ⁴(2x)

Substitute 2x = t 2dx = dt dx = (1)/(2)dt. When x = 0 t = 0, and when x = (π)/(4) t = (π)/(2).

I = (1)/(4) ∫₀(π)/(2) t dt ⁴t + ⁴t (1)
Step 1: Apply King's Property

Applying the property ∫₀a f(t) dt = ∫₀a f(a-t) dt:

I = (1)/(4) ∫₀(π)/(2) ((π)/(2) - t) dt ⁴((π)/(2)-t) + ⁴((π)/(2)-t) I = (1)/(4) ∫₀(π)/(2) ((π)/(2) - t) dt ⁴t + ⁴t (2)

Adding equations (1) and (2):

2I = (1)/(4) ∫₀(π)/(2) (π)/(2) dt ⁴t + ⁴t 2I = (π)/(8) ∫₀(π)/(2) dt ⁴t + ⁴t 2I = (π)/(8) ∫₀(π)/(2) ⁴t dt ⁴t + 1 2I = (π)/(8) ∫₀(π)/(2) (1 + ²t) ²t dt ⁴t + 1
Step 2: Substitution and Algebraic Limits

Let t = y ²t dt = dy. When t = 0 y = 0, and when t = (π)/(2) y = ∞.

2I = (π)/(8) ∫₀∞ (1 + y²) dy1 + y⁴ I = (π)/(16) ∫₀∞ 1 + 1y²y² + 1y² dy

Now put y - (1)/(y) = p (1 + 1y²) dy = dp. When y → 0^+ p → -∞, and when y → ∞ p → ∞. Also, y² + 1y² = p² + 2 = p² + (√(2))².

I = (π)/(16) ∫-∞∞ dpp² + (√(2))² I = π16√(2) [ ⁻¹( p√(2)) ]-∞∞ I = π16√(2) ( (π)/(2) - (-(π)/(2)) ) = π²16√(2) = √(2)π²32$$
Pattern Recognition

Sees: Integrand containing

Pattern Recognition

Sees: Integrand containing $xin the numerator and symmetric trigonometric functions in the denominator. Shortcut: The elimination ofxusing King's property is standard. For integrals containing\frac{1+y^2}{1+y^4}, dividing byy^2transforms the denominator into a perfect square form\left(y-\frac{1}{y}\right)^2+2$, making substitution trivial.

Chapter Mix

Class 12 Mathematics: Definite Integrals Class 11 Mathematics: Trigonometric Identities

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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%)