If the domain of the function ₅(18x - x² -77) is (α ,β) and the domain of the function (x - 1)((2x² + 3x - 2)/(x² - 3x - 4)) is (γ ,δ), then \alpha^2 +\beta^2 +\gamma^2 is equal to:

Solution & Explanation

Related Formula

For a logarithmic term b(a) to be valid:

a > 0, b > 0, b ≠ 1
Core Logic

Analyzing the first function f₁(x) = ₅(18x - x² - 77):

18x - x² - 77 > 0 x² - 18x + 77 < 0 (x - 7)(x - 11) < 0 x in (7, 11)

Hence, α = 7, β = 11.

Step 1: Check Second Function Base and Argument

Analyzing f₂(x) = (x - 1)((2x² + 3x - 2)/(x² - 3x - 4)):

Base constraints:

x - 1 > 0 x > 1 x - 1 ≠ 1 x ≠ 2

Argument constraints:

(2x² + 3x - 2)/(x² - 3x - 4) > 0 ((2x - 1)(x + 2))/((x - 4)(x + 1)) > 0
Step 2: Apply Sign Scheme

Using the wave-curve method to determine where the rational fraction is positive:

Domain of a Function diagram for Q54 - JEE Main 2025 Evening
Domain of a Function diagram for Q54 - JEE Main 2025 Evening

Combining this with x > 1 and x ≠ 2, the common interval is:

x in (4, ∞)

Thus, γ = 4.

Step 3: Calculate final sum
α² + β² + γ² = 7² + 11² + 4² = 49 + 121 + 16 = 186
Pattern Recognition

For domain intersections involving variables in both the log base and argument, always list base rules (>0, ≠ 1) first to eliminate invalid sign fields early on.

Chapter Mix

Class 11 Mathematics: Relations and Functions

Reference Study Guides

More Relations and Functions Previous-Year Questions

Q1 jee_main_2026_21_jan_morning Domain and Range of Inverse Trigonometric Functions
If the domain of the function f(x) = ⁻¹((2x - 5)/(11 - 3x)) + ⁻¹(2x² - 3x + 1) is the interval [α, β] , then α + 2β is equal to :
  • A. 1
  • B. 3
  • C. 5
  • D. 2

Solution

### Related Formula For inverse trigonometric functions ⁻¹(g(x)) and ⁻¹(h(x)), the arguments must satisfy: -1 ≤ g(x) ≤ 1 -1 ≤ h(x) ≤ 1 ### Core Logic Given f(x) = ⁻¹((2x - 5)/(11 - 3x)) + ⁻¹(2x² - 3x + 1) We establish two simultaneous inequalities for the domain: 1) -1 ≤ (2x - 5)/(11 - 3x) ≤ 1 2) -1 ≤ 2x² - 3x + 1 ≤ 1 ### Step 1: Solve the Quadratic Inequality From -1 ≤ 2x² - 3x + 1 ≤ 1: Split into two parts: 2x² - 3x + 2 ≥ 0 (This is always true as discriminant D < 0, a > 0) 2x² - 3x ≤ 0 ⇒ x(2x - 3) ≤ 0 x in [0, (3)/(2)] (i) ### Step 2: Solve the Rational Inequality From -1 ≤ (2x - 5)/(11 - 3x) ≤ 1: Part A: (2x - 5)/(11 - 3x) + 1 ≥ 0 ⇒ (2x - 5 + 11 - 3x)/(11 - 3x) ≥ 0 ⇒ (6 - x)/(11 - 3x) ≥ 0
Domain interval number line diagram for Q1 - JEE Main 2026 Morning
Domain interval number line diagram for Q1 - JEE Main 2026 Morning
x in (-∞, (11)/(3)) [6, ∞) Part B: (2x - 5)/(11 - 3x) - 1 ≤ 0 ⇒ (5x - 16)/(11 - 3x) ≤ 0 ⇒ x in (-∞, (16)/(5)] ((11)/(3), ∞) Intersection of Part A and Part B: x in (-∞, (16)/(5)] [6, ∞) (ii) ### Step 3: Final Intersection Taking the intersection of (i) and (ii): x in [0, (3)/(2)] Comparing this with [α, β], we have α = 0, β = (3)/(2). Therefore, α + 2β = 0 + 2((3)/(2)) = 3 ### Pattern Recognition Whenever dealing with dual inverse trig terms, strictly isolate the bounding intervals [-1, 1] for each argument separately and use a number line intersection to find the strictest common region. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Maths: Functions Class 11 Maths: Linear Inequalities
Q3 jee_main_2026_21_jan_morning Number of Reflexive and Symmetric Relations
The number of relations, defined on the set a, b, c, d , which are both reflexive and symmetric, is equal to:
  • A. 256
  • B. 16
  • C. 1024
  • D. 64

Solution

### Related Formula For a set with n elements, the number of relations that are both reflexive and symmetric is given by: 2(n(n-1))/(2) ### Core Logic A reflexive relation must contain all diagonal pairs (x,x). There is only 1 way to assign these elements (they MUST be present). A symmetric relation requires that if (x,y) is present, (y,x) must also be present. Thus, we only have the freedom to choose whether to include the unordered pairs x, y where x ≠ y. ### Step 1: Calculate the available independent pairs Number of distinct elements n = 4. Total number of pairs in the cartesian product is n² = 16. Number of diagonal pairs (reflexive necessity) = n = 4. Remaining non-diagonal pairs = 16 - 4 = 12. Since symmetry pairs them up (a,b) rightarrow (b,a), there are exactly (12)/(2) = 6 independent choices. ### Step 2: Calculate total relations Each of the 6 independent pairs can either be included or excluded (2 choices). Total relations = 1⁴ × 2⁶ = 64. ### Pattern Recognition Memorize the combinatorics of binary relations for n elements: Total = 2n², Reflexive = 2n(n-1), Symmetric = 2n(n+1)/2, Reflexive & Symmetric = 2n(n-1)/2. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Maths: Sets and Relations
Q13 jee_main_2026_21_jan_evening Operations on Sets
Let A = x : |x² - 10| ≤ 6 and B = x : |x - 2| > 1. Then
  • A. A B = (-∞, 1] (2, ∞)
  • B. A - B = [2, 3)
  • C. A B = [-4, -2] [3, 4]
  • D. B - A = (-∞, -4) (-2, 1) (4, ∞)

Solution

### Related Formula |X| ≤ a -a ≤ X ≤ a |X| > a X < -a or X > a ### Core Logic Expand both set definitions onto the real number line to find explicit intervals for A and B, then apply set operations to verify the options. ### Step 1: Simplify Set A |x² - 10| ≤ 6 -6 ≤ x² - 10 ≤ 6 4 ≤ x² ≤ 16 This yields x in [-4, -2] [2, 4]. So, A = [-4, -2] [2, 4]. ### Step 2: Simplify Set B |x - 2| > 1 x - 2 < -1 or x - 2 > 1 x < 1 or x > 3 So, B = (-∞, 1) (3, ∞). ### Step 3: Evaluate Options A B = (-∞, 1) [2, ∞) (Option 1 is wrong, has 1]) A B = [-4, -2] (3, 4] (Option 3 is wrong, has [3,4]) A - B = A B^c. B^c = [1, 3]. A [1, 3] = [2, 3]. (Option 2 is wrong, has [2, 3)) B - A = B A^c. A^c = (-∞, -4) (-2, 2) (4, ∞). B A^c = (-∞, -4) (-2, 1) (4, ∞). This matches Option 4 perfectly. ### Pattern Recognition Draw inequalities involving absolute values directly onto a single number line graph to perform union and intersection operations without logic gaps. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Maths: Sets and Relations
Q17 jee_main_2026_21_jan_evening Types of Relations
Let A = 2, 3, 5, 7, 9. Let R be the relation on A defined by xRy if and only if 2x ≤ 3y. Let be the number of elements in R, and m be the minimum number of elements required to be added in R to make it a symmetric relation. Then + m is equal to:
  • A. 23
  • B. 25
  • C. 21
  • D. 27

Solution

### Related Formula A relation R is symmetric if (x,y) in R (y,x) in R. ### Core Logic Check condition y ≥ (2x)/(3) for each x in A = 2, 3, 5, 7, 9 to generate ordered pairs (x,y). Count the pairs to get . Then find asymmetric pairs to get m. ### Step 1: Enumerate elements of R x = 2 y ≥ 4/3 = 1.33 y in 2, 3, 5, 7, 9 (5 elements) x = 3 y ≥ 6/3 = 2 y in 2, 3, 5, 7, 9 (5 elements) x = 5 y ≥ 10/3 = 3.33 y in 5, 7, 9 (3 elements) x = 7 y ≥ 14/3 = 4.66 y in 5, 7, 9 (3 elements) x = 9 y ≥ 18/3 = 6 y in 7, 9 (2 elements) Total elements in R is = 5 + 5 + 3 + 3 + 2 = 18. ### Step 2: Determine Missing Symmetric Pairs We need to check which reverse pairs (y,x) are missing. (2, 5) in R, but (5, 2) R. (2, 7) in R, but (7, 2) R. (2, 9) in R, but (9, 2) R. (3, 5) in R, but (5, 3) R. (3, 7) in R, but (7, 3) R. (3, 9) in R, but (9, 3) R. (5, 9) in R, but (9, 5) R. These are m = 7 pairs that need to be added. Thus, + m = 18 + 7 = 25. ### Pattern Recognition When counting pairs for small sets, list them manually by rows. To make symmetric, any non-diagonal pair (x,y) that is present while (y,x) is absent counts as 1 missing element. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Maths: Sets and Relations
Q2 jee_main_2026_22_january_morning Symmetric Relation
Let the relation R on the set M = 1, 2, 3, …, 16 be given by R = (x, y) : 4y = 5x - 3, x, y in M. Then the minimum number of elements required to be added in R, in order to make the relation symmetric, is equal to
  • A. 1
  • B. 2
  • C. 4
  • D. 3

Solution

### Related Formula A relation R is symmetric if (a,b) in R (b,a) in R ### Core Logic Given 4y = 5x - 3 y = (5x - 3)/(4). We evaluate this for x in 1, 2, …, 16 such that y is also an integer in the same set. - If x = 3 y = (15 - 3)/(4) = 3 (3,3) in R - If x = 7 y = (35 - 3)/(4) = 8 (7,8) in R - If x = 11 y = (55 - 3)/(4) = 13 (11,13) in R - If x = 15 y = (75 - 3)/(4) = 18 M Therefore, R = (3,3), (7,8), (11,13) ### Step 1: Identifying Missing Symmetric Elements To make the relation symmetric, for every (x,y) in R, the pair (y,x) must also belong to R. - (3,3) is symmetric to itself. - For (7,8), we must add (8,7). - For (11,13), we must add (13,11). Thus, the required elements to be added are (8,7) and (13,11), which totals 2 elements. ### Pattern Recognition When evaluating linear Diophantine equations over a small finite set, simply substitute modular values (here, 5x - 3 ≡ 0 4) to find the explicit ordered pairs, then mechanically apply the equivalence property criteria. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Maths: Sets, Relations and Functions

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