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Conic Sections appeared 94 times across 3 years — 10.9% of Mathematics. This question is from Hyperbola - Latus Rectum and Eccentricity.

Year 2026 2025 2024 Total
Questions 29 44 21 94

Let H₁: x²a²- y²b²=1 and H₂:- x²A²+ y²B²=1 be two hyperbolas having length of latus rectums 15√(2) and 12√(5) respectively. Let their eccentricities be e₁=√((5)/(2)) and e₂ respectively. If the product of the lengths of their transverse axes is 100√(10) then 25e₂² is equal to \_\_\_\_.

Numerical Answer Type:
Enter a numerical value Answer: 55 +4 marks

Solution & Explanation

Related Formula
  • For standard hyperbola (x²)/(a²) - (y²)/(b²) = 1: Latus Rectum = (2b²)/(a), transverse axis length = 2a, eccentricity relation b² = a²(e² - 1).
  • For conjugate hyperbola -(x²)/(A²) + (y²)/(B²) = 1: Latus Rectum = (2A²)/(B), transverse axis length = 2B, eccentricity relation A² = B²(e² - 1).
Step 1: Solve Parameters for Hyperbola H₁

Given latus rectum and eccentricity parameters:

(2b²)/(a) = 15√(2) e₁² = 1 + (b²)/(a²) = (5)/(2) ⇒ (b²)/(a²) = (3)/(2) ⇒ b² = (3)/(2)a²

Substitute b² into latus rectum equation:

(2((3)/(2)a²))/(a) = 3a = 15√(2) ⇒ a = 5√(2) b² = (3)/(2)(50) = 75 ⇒ b = 5√(3)

Transverse axis length of H₁ = 2a = 10√(2).

Step 2: Solve Parameters for Hyperbola H₂

The product of their transverse axes lengths equals 100√(10):

2a · 2B = 100√(10) ⇒ 10√(2) · 2B = 100√(10) ⇒ 2B = 10√(5) ⇒ B = 5√(5)

Given latus rectum for conjugate hyperbola H₂:

(2A²)/(B) = 12√(5) ⇒ 2A²5√(5) = 12√(5) ⇒ 2A² = 60 × 5 = 300 ⇒ A² = 150
Step 3: Calculate 25e₂²

Find e₂² using the conjugate eccentricity relation :

e₂² = 1 + (A²)/(B²) = 1 + 150(5√(5))² = 1 + (150)/(125) = 1 + (6)/(5) = (11)/(5)

Compute 25e₂² [cite: 3418, 4107]:

25e₂² = 25 × (11)/(5) = 55
Pattern Recognition

Pay extra attention to conjugate-type equations (-(x²)/(A²) + (y²)/(B²) = 1). For these vertical hyperbolas, the transverse axis corresponds to the variable with the positive sign (2B), and the components inside the latus rectum swap positions proportionally.

Chapter Mix

Class 11 Mathematics: Conic Sections

Reference Study Guides

More Conic Sections Previous-Year Questions — Page 2

Q6 jee_main_2026_21_jan_evening Parabola
Let one end of a focal chord of the parabola y²=16x be (16, 16). If P(α,β) divides this focal chord internally in the ratio 5:2, then the minimum value of α+β is equal to:
  • A. 22
  • B. 7
  • C. 5
  • D. 16

Solution

Related Formula
For a focal chord with ends (at₁², 2at₁) and (at₂², 2at₂), the relation is t₁t₂ = -1 Section formula: (x, y) = ( (mx₂ + nx₁)/(m+n), (my₂ + ny₁)/(m+n) )
Core Logic

Parabola focal chord division diagram for Q6 - JEE Main 2026 Evening
Parabola focal chord division diagram for Q6 - JEE Main 2026 Evening
For y² = 16x, a = 4. The given point A(16, 16) is equivalent to 4t² = 16 and 2(4)t = 16, which gives parameter t₁ = 2. The other end B has parameter t₂ = -(1)/(t₁) = -(1)/(2).

Step 1: Calculate coordinates of B

For t₂ = -1/2, point B is: x = 4(-1/2)² = 1 y = 8(-1/2) = -4 So, B(1, -4).

Step 2: Section formula calculations (Two cases)

Point P(α, β) divides AB in the ratio 5:2. There are two possibilities depending on which end the ratio starts from.

Case 1: Ratio 5 from B to A (i.e. A is x₂ and B is x₁):

α = (5(16) + 2(1))/(7) = (80 + 2)/(7) = (82)/(7) β = (5(16) + 2(-4))/(7) = (80 - 8)/(7) = (72)/(7)

Sum: α + β = (154)/(7) = 22.

Case 2: Ratio 5 from A to B (i.e. B is x₂ and A is x₁):

α = (5(1) + 2(16))/(7) = (5 + 32)/(7) = (37)/(7) β = (5(-4) + 2(16))/(7) = (-20 + 32)/(7) = (12)/(7)

Sum: α + β = (49)/(7) = 7.

Step 3: Minimum Value

Comparing the two possible sums, 7 < 22. Thus, the minimum value is 7.

Pattern Recognition

When a line segment is divided in a given ratio, 'internal division' inherently bears two solutions based on the orientation (from point A or point B). Always evaluate both cases when finding a minimum or maximum.

Chapter Mix

Class 11 Maths: Conic Sections

Q25 jee_main_2026_21_jan_evening Locus
If P is a point on the circle x² + y² = 4, Q is a point on the straight line 5x + y + 2 = 0 and x - y + 1 = 0 is the perpendicular bisector of PQ, then 13 times the sum of abscissa of all such point P is ____.
Numerical Answer. Answer: 2 to 2

Solution

Related Formula
Perpendicular bisector properties: m₁m₂ = -1 and mid-point lies on the line. Parametric point on circle x²+y²=r² is (r θ, r θ)
Core Logic

Circle locus perpendicular bisector diagram for Q25 - JEE Main 2026 Evening
Circle locus perpendicular bisector diagram for Q25 - JEE Main 2026 Evening
Let P = (2 θ, 2 θ). Let Q on the line 5x + y + 2 = 0 be Q(α, -5α-2). The line x - y + 1 = 0 is the perpendicular bisector of PQ. This gives two conditions: slope of PQ is -1, and mid-point of PQ satisfies the bisector equation.

Step 1: Apply Slope Condition

Slope of bisector is 1, so slope of PQ must be -1.

(2 θ - (-5α - 2))/(2 θ - α) = -1 2 θ + 5α + 2 = -2 θ + α θ + θ + 2α + 1 = 0 (1)
Step 2: Apply Midpoint Condition

Midpoint of PQ is ( (2 θ + α)/(2), (2 θ - 5α - 2)/(2) ). Substitute into x - y + 1 = 0:

(2 θ + α)/(2) - (2 θ - 5α - 2)/(2) + 1 = 0 2 θ + α - 2 θ + 5α + 2 + 2 = 0 θ - θ + 3α + 2 = 0 (2)
Step 3: Eliminate alpha and Solve

From (1), 2α = - θ - θ - 1 α = (- θ - θ - 1)/(2). Substitute α into (2):

θ - θ + 3( (- θ - θ - 1)/(2) ) + 2 = 0 2 θ - 2 θ - 3 θ - 3 θ - 3 + 4 = 0 - θ - 5 θ + 1 = 0 θ + 5 θ = 1

Let's express in half angles:

1 - 2 ²(θ)/(2) + 10 (θ)/(2) (θ)/(2) = 1 2 (θ)/(2) ( 5 (θ)/(2) - (θ)/(2) ) = 0

So, (θ)/(2) = 0 θ = 1 or (θ)/(2) = 5 θ = (1 - ²(θ/2))/(1 + ²(θ/2)) = (1 - 25)/(1 + 25) = -(24)/(26) = -(12)/(13).

Step 4: Final Calculation

The abscissa of P is 2 θ. Values of abscissa are 2(1) = 2 and 2(-(12)/(13)) = -(24)/(13). Sum of abscissa values = 2 - (24)/(13) = (26 - 24)/(13) = (2)/(13). We need 13 × (Sum) = 13 × (2)/(13) = 2.

Pattern Recognition

Instead of finding the image of a generic circle point in a line, construct the reflection point Q parameter, use slope logic (m₁m₂=-1) and midpoint logic simultaneously to create a trigonometric linear equation.

Chapter Mix

Class 11 Maths: Circles Class 11 Maths: Straight Lines

Q10 jee_main_2026_22_january_morning Hyperbola and Line Intersection
If the line α x + 2y = 1, where α in R, does not meet the hyperbola x² - 9y² = 9, then a possible value of α is:
  • A. 0.6
  • B. 0.8
  • C. 0.5
  • D. 0.7

Solution

Related Formula
For a line y = mx + c and hyperbola (x²)/(a²) - (y²)/(b²) = 1: If they do not intersect, the quadratic in x formed by substituting y has D < 0.
Core Logic

Given line: α x + 2y = 1 y = (1 - α x)/(2). Given hyperbola: x² - 9y² = 9.

Substitute the expression for y into the hyperbola's equation:

x² - 9((1 - α x)/(2))² = 9
Step 1: Solving for Discriminant
x² - (9(1 - 2α x + α² x²))/(4) = 9

Multiply by 4:

4x² - 9(1 - 2α x + α² x²) = 36 4x² - 9 + 18α x - 9α² x² - 36 = 0 (4 - 9α²)x² + 18α x - 45 = 0

For the line to NOT intersect the hyperbola, the quadratic must yield non-real roots, meaning Discriminant D < 0.

D = (18α)² - 4(4 - 9α²)(-45) < 0 324α² + 180(4 - 9α²) < 0 324α² + 720 - 1620α² < 0 -1296α² + 720 < 0 1296α² > 720 α² > (720)/(1296) = (5)/(9)
Step 2: Finding Alpha Interval
α² - (5)/(9) > 0 α in (-∞, - √(5)3) ( √(5)3, ∞)

Since √(5) ≈ 2.236, we have √(5)3 ≈ 0.745. So α must be strictly greater than 0.745 (or less than -0.745).

Checking the given options: (1) 0.6 (No) (2) 0.8 (Yes, 0.8 > 0.745) (3) 0.5 (No) (4) 0.7 (No)

Pattern Recognition

Geometrically, for a line not to meet a hyperbola, its slope must lie within a specific range determined by the asymptotes (m = ± b/a), and its c² must satisfy c² < a²m² - b². Direct substitution to enforce D < 0 is purely mechanical and robust.

Chapter Mix

Class 11 Maths: Conic Sections

Q12 jee_main_2026_22_january_morning Intersection of Two Circles
Let the set of all values of r, for which the circles (x + 1)² + (y + 4)² = r² and x² + y² - 4x - 2y - 4 = 0 intersect at two distinct points be the interval (α, β). Then αβ is equal to
  • A. 25
  • B. 20
  • C. 21
  • D. 24

Solution

Related Formula
Two circles intersect at distinct points if |r₁ - r₂| < d < r₁ + r₂

where d is the distance between their centers.

Core Logic

Circle 1: (x + 1)² + (y + 4)² = r² Center C₁ = (-1, -4) and Radius r₁ = r.

Circle 2: x² + y² - 4x - 2y - 4 = 0 (x - 2)² + (y - 1)² = 3² Center C₂ = (2, 1) and Radius r₂ = 3.

Step 1: Distance Between Centers

Distance d between C₁ and C₂:

d = √((2 - (-1))² + (1 - (-4))²) d = √(3² + 5²) = √(9 + 25) = √(34)
Step 2: Applying the Intersection Condition

For two distinct intersection points:

|r - 3| < √(34) < r + 3

Breaking this down into two inequalities:

  • |r - 3| < √(34) -√(34) < r - 3 < √(34) 3 - √(34) < r < 3 + √(34)
  • r + 3 > √(34) r > √(34) - 3
  • Since radius r > 0, taking the intersection of the conditions:

r in (√(34) - 3, √(34) + 3)

Thus, α = √(34) - 3 and β = √(34) + 3.

Step 3: Calculating Final Product
αβ = (√(34) - 3)(√(34) + 3) = 34 - 9 = 25
Pattern Recognition

Intersection of two circles boils down to the fundamental triangle inequality relating the radii to the center distance: |r₁ - r₂| < d < r₁ + r₂. Solving this naturally yields an interval (α, β) formatted as a difference of squares upon multiplication.

Chapter Mix

Class 11 Maths: Circles

Q17 jee_main_2026_22_january_morning Properties of Parabola
If the chord joining the points P₁(x₁, y₁) and P₂(x₂, y₂) on the parabola y² = 12x subtends a right angle at the vertex of the parabola, then x₁x₂ - y₁y₂ is equal to
  • A. 288
  • B. 280
  • C. 284
  • D. 292

Solution

Related Formula
If a chord joining t₁ and t₂ subtends a right angle at the vertex (0,0), then t₁ t₂ = -4. Parametric coordinates for y² = 4ax: (at², 2at)
Core Logic

Given parabola y² = 12x 4a = 12 a = 3.

Let the points be P₁(x₁, y₁) = (3t₁², 6t₁) and P₂(x₂, y₂) = (3t₂², 6t₂).

Since the chord subtends a right angle at the vertex (origin),

mOP₁ · mOP₂ = -1 (6t₁)/(3t₁²) · (6t₂)/(3t₂²) = -1 (2)/(t₁) · (2)/(t₂) = -1 t₁ t₂ = -4
Step 1: Calculating the Expression

We need to evaluate x₁ x₂ - y₁ y₂:

x₁ x₂ = (3t₁²)(3t₂²) = 9(t₁ t₂)² y₁ y₂ = (6t₁)(6t₂) = 36(t₁ t₂)

Substitute t₁ t₂ = -4:

x₁ x₂ - y₁ y₂ = 9(-4)² - 36(-4)

= 9(16) + 144

= 144 + 144 = 288
Pattern Recognition

Right angles subtended at the vertex by a chord on y² = 4ax instantly lock the parameter product to t₁ t₂ = -4. Substitute this directly into any coordinate products required by the problem.

Chapter Mix

Class 11 Maths: Conic Sections

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