Let f(α) denote the area of the region in the first quadrant bounded by x = 0, x = 1, y² = x and y = |α x - 5| - |1 - α x| + α x². Then (f(0) + f(1)) is equal to

Solution & Explanation

Related Formula
Area = ∫x₁x₂ (yupper - ylower) dx
Core Logic

Evaluate f(0) by setting α = 0 in the function for y.

At α = 0 y = |0· x - 5| - |1 - 0· x| + 0· x²

y = |-5| - |1| = 5 - 1 = 4

So for f(0), the bounded area A₁ is between y = 4, y = √(x), from x = 0 to x = 1.

Area bounded by Modulus and Parabola
Area bounded by Modulus and Parabola

Step 1: Calculating f(0)
A₁ = ∫₀¹ (4 - √(x)) dx = [ 4x - x3/23/2 ]₀¹ = 4(1) - (2)/(3)(1) = (10)/(3)

So, f(0) = (10)/(3).

Step 2: Determining curve for f(1)

Evaluate f(1) by setting α = 1 in the function for y.

At α = 1 y = |x - 5| - |1 - x| + x². Since the area is restricted to x in [0, 1]: x - 5 is negative, so |x - 5| = 5 - x. 1 - x is positive, so |1 - x| = 1 - x.

y = (5 - x) - (1 - x) + x² y = 5 - x - 1 + x + x² = 4 + x²

Area bounded by Modulus and Parabola
Area bounded by Modulus and Parabola

Step 3: Calculating f(1)

For f(1), the bounded area A₂ is between y = 4 + x² and y = √(x), from x = 0 to x = 1.

A₂ = ∫₀¹ ((4 + x²) - √(x)) dx = [ 4x + (x³)/(3) - x3/23/2 ]₀¹ = ( 4 + (1)/(3) - (2)/(3) ) = 4 - (1)/(3) = (11)/(3)

So, f(1) = (11)/(3).

Step 4: Final Sum
|f(0) + f(1)| = | A₁ + A₂ | = | (10)/(3) + (11)/(3) | = (21)/(3) = 7

Area bounded by Modulus and Parabola
Area bounded by Modulus and Parabola

Pattern Recognition

Modulus functions combined with parametric limits should be instantly resolved by plugging in the bounds of x (here [0,1]) to drop the absolute value signs before attempting any integral.

Chapter Mix

Class 12 Maths: Area Under the Curve Class 11 Maths: Modulus Function

Reference Study Guides

More Area Under the Curve 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

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%)