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%)

Let A = \-3, -2, -1, 0, 1, 2, 3\[cite: 555]. Let R be a relation on A defined by xRy if and only if 0 le x^2 + 2y le 4[cite: 555]. Let l 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 reflexive relation[cite: 556, 557]. Then l + m is equal to[cite: 558]:

Solution & Explanation

### Related Formula 1. Elements in a relation satisfy the exact range constraint. 2. Reflexive criteria: For every x in A, (x, x) in R. ### Core Logic Rewrite the inequality to isolate variables systematically [cite: 1235]: -2y le x^2 le 4-2y [cite: 1235] Test every valid value of y in A to discover valid integer values for x[cite: 1237, 1238, 1241, 1259, 1260, 1261]: - y = -3 implies 6 le x^2 le 10 implies x in \-3, 3\ - y = -2 implies 4 le x^2 le 8 implies x in \-2, 2\ - y = -1 implies 2 le x^2 le 6 implies x in \-2, 2\ - y = 0 implies 0 le x^2 le 4 implies x in \-2, -1, 0, 1, 2\ - y = 1 implies -2 le x^2 le 2 implies x in \-1, 0, 1\ - y = 2 implies -4 le x^2 le 0 implies x in \0\ - y = 3 implies -6 le x^2 le -2 implies textNo real x text exists ### Step 1: Listing set elements and counting Compile all distinct matching coordinate pairs (x,y) into set R [cite: 1264]: R = \(-3,-3), (-3,3), (-2,-2), (-2,2), (-1,-2), (-1,2), (0,-2), (0,-1), (0,0), (0,1), (0,2), (1,-1), (1,0), (1,1), (2,0)\ [cite: 1264] Counting elements gives [cite: 1265]: l = 15 [cite: 1265] To make the relation reflexive, the pairs (-3,-3), (-2,-2), (-1,-1), (0,0), (1,1), (2,2), (3,3) must all belong to R. Checking missing elements [cite: 1267]: \(-1,-1), (2,2), (3,3)\ implies m = 3 [cite: 1267] Sum of variables [cite: 1268]: l + m = 15 + 3 = 18 [cite: 1268] ### Pattern Recognition Isolating terms explicitly via a variable-by-variable bounded testing grid avoids missing distinct coordinate boundary values. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Mathematics: Relations and Functions

Reference Study Guides

More Relations and Functions Previous-Year Questions — Page 2

Q62 2025 Domain of Functions
If the domain of the function f(x) = log_7(1 - log_4(x^2 - 9x + 18)) is (alpha, beta) cup (gamma, delta), then \text{sum } alpha + beta + gamma + delta is equal to
  • A. 18
  • B. 16
  • C. 15
  • D. 17

Solution

### Related Formula For a logarithmic term log_b(g(x)) to be defined: - g(x) > 0 - b > 0, b neq 1 ### Core Logic Let's set defining inequalities sequentially: 1. Inside the outer logarithm: 1 - log_4(x^2 - 9x + 18) > 0 implies log_4(x^2 - 9x + 18) < 1 Since base is 4 > 1: x^2 - 9x + 18 < 4 implies x^2 - 9x + 14 < 0 (x-2)(x-7) < 0 implies x in (2, 7) quad text--- (1) ### Step 1: Finding bounds for inner logarithmic term 2. Inside the inner logarithm: x^2 - 9x + 18 > 0 (x-3)(x-6) > 0 implies x in (-infty, 3) cup (6, infty) quad text--- (2) ### Step 2: Intersection of regions Taking the intersection of (1) and (2): x in (2, 3) cup (6, 7) This gives: alpha = 2, quad beta = 3, quad gamma = 6, quad delta = 7 Calculating the sum: alpha + beta + gamma + delta = 2 + 3 + 6 + 7 = 18 ### Pattern Recognition Logarithmic domains must check arguments from the innermost level to the outermost level. Remember that bases >1 maintain inequality direction upon exponentiation, while bases <1 reverse it. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Mathematics: Relations and Functions
Q 2025 Types of Relations
The number of relations on the set mathrmA = \1, 2, 3\ containing at most 6 elements including (1, 2), which are reflexive and transitive but not symmetric, is
Numerical Answer. Answer: 5 to 6

Solution

### Related Formula For a relation R on set A = \1, 2, 3\: - **Reflexive**: Must contain \(1,1), (2,2), (3,3)\. - **Transitive**: If (a,b) in R and (b,c) in R, then (a,c) in R. - **Not Symmetric**: Contains at least one element (a,b) whose inverse (b,a) notin R. ### Core Logic Since R is reflexive, it must contain exactly 3 initial diagonal elements: R_textbase = \(1,1), \, (2,2), \, (3,3)\ We are given that (1,2) in R. So R must contain at least these 4 mandatory pairs: R supseteq \(1,1), \, (2,2), \, (3,3), \, (1,2)\ Total elements currently = 4. The problem sets a boundary constraint of le 6 total elements. Available remaining elements to selectively append: (2,1), (2,3), (1,3), (3,1), (3,2). ### Step 1: Analyze Cases based on Element Length - **Case 1**: Exactly 4 elements. R = \(1,1), (2,2), (3,3), (1,2)\ This is reflexive, transitive, and not symmetric (since (2,1) notin R). implies 1 text way. ### Step 2: Evaluate 5 and 6 Element Configurations - **Case 2**: Exactly 5 elements. We add one pair from the available pool. To ensure transitivity, we choose pairs like (1,3) or (3,2). - If we add (1,3): R = dots cup \(1,3)\ implies valid (transitive, non-symmetric). - If we add (3,2): R = dots cup \(3,2)\ implies valid. Adding (2,1) or others directly breaks either transitivity or symmetric constraints. implies 2 text ways. - **Case 3**: Exactly 6 elements. Valid configuration groups that satisfy all transitive linkages without triggering full symmetry across the board are: 1. \(2,3), (1,3)\ added 2. \(1,3), (3,2)\ added 3. \(3,1), (3,2)\ added This yields 3 text ways. ### Step 3: Calculate the Comprehensive Sum Sum the valid configurations across all operational boundaries: textTotal Relations = 1 + 2 + 3 = 6 quad (textour Analysis) *(Note: Official NTA keys accepted 5 due to variant interpretation filters on transitivity bounds).* ### Pattern Recognition When dealing with small set elements counts like n=3, building explicit tracking trees of allowed pairs is far safer than calculating raw combinations using generalized formula subsets. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Mathematics: Relations and Functions
Q65 2025 Types of Relations
Let mathrmA = \0, 1, 2, 3, 4, 5\. Let mathrmR be a relation on mathrmA defined by (mathrmx, mathrmy) in mathrmR if and only if max \mathrmx, mathrmy\ in \3, 4\. Then among the statements (S_1) : The number of elements in R is 18, and (S_2) : The relation R is symmetric but neither reflexive nor transitive
  • A. both are true
  • B. both are false
  • C. only (mathrmS_2) is true
  • D. only (mathbfS_1) is true

Solution

### Related Formula max(x,y) = max(y,x) ### Core Logic Enumerate order metrics generated by the max mapping filter to assess population sizes and map properties against equivalence rule standards. ### Step 1: Enumerate Set Components Listing combinations matching the upper caps constraint parameters: R = \(0, 3), (3, 0), (0, 4), (4, 0), (1, 3), (3, 1), (1, 4), (4, 1), (2, 3), (3, 2), (2, 4), (4, 2), (3, 3), (3, 4), (4, 3), (4, 4)\ Total element count equals 16 items. Therefore, statement S_1 is false. ### Step 2: Analyze Reflexivity and Symmetry Properties * Symmetry: Order switches do not alter peak size values. Since (x,y) in R implies (y,x) in R, symmetry holds. * Reflexivity: Disjoint small pairs like (0,0) present peak values below target requirements, breaking reflexivity equations. ### Step 3: Test Transitivity Bounds Pick subset tracking variables showing breakdown trends: (0,3) in R quad textand quad (3,1) in R However, direct boundary tracking combination elements (0,1) notin R because max(0,1) = 1 notin \3,4\. Thus, transitivity fails. Only S_2 maps correctly. ### Pattern Recognition Max properties natively preserve system balance ordering directions, establishing automatic symmetry maps but struggling with linked cascading elements needed for transitivity rules. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Mathematics: Relations and Functions
Q72 2025 Domain of Functions
Let the domain of the function mathrmf(x) = cos^-1left(frac4x + 53x - 7right) be [alpha ,beta ] and the domain of mathbfg(mathbfx) = log_2(2 - 6log_27(2mathbfx + 5)) be (gamma ,delta). Then |7(alpha + beta) + 4(gamma + delta)| is equal to
Numerical Answer. Answer: 96 to 96

Solution

### Related Formula -1 le textarg(cos^-1) le 1 textarg(log) > 0 ### Core Logic Isolate boundary inputs on logarithmic filters and inverse cosine boundaries using simple inequality signs to extract set endpoints. ### Step 1: Solve Inverse Cosine Bounds -1 le frac4x+53x-7 le 1 implies frac7x-23x-7 ge 0 quad textand quad fracx+123x-7 le 0 {{SOL_IMG_72_1}} {{SOL_IMG_72_2}} Intersecting sets maps out: [-12, 2/7] implies alpha = -12, beta = frac27 ### Step 2: Solve Logarithmic Core Domain 2 - 6log_27(2x+5) > 0 implies log_27(2x+5) < frac13 2x + 5 < 27^1/3 = 3 implies x < -1 Also structural logging arguments force: 2x+5 > 0 implies x > -5/2. Domain is: (-5/2, -1) implies gamma = -frac52, delta = -1 ### Step 3: Combined Metric Equation left| 7(alpha + beta) + 4(gamma + delta) right| = left| 7left(-12 + frac27right) + 4left(-frac52 - 1right) right| = |-82 - 14| = 96 ### Pattern Recognition Always align multiple bounds tracks sequentially. Missing internal tracking restrictions like checking if base log variables stay over zero can alter endpoint coordinates. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Mathematics: Relations and Functions
Q54 2025 Domain of a Function
If the domain of the function log_5left(18x - x^2 -77 ight) is (alpha ,beta) and the domain of the function log_(x - 1)left(frac2x^2 + 3x - 2x^2 - 3x - 4right) is (gamma ,delta), then \alpha^2 +\beta^2 +\gamma^2 is equal to:
  • A. 174
  • B. 179
  • C. 186
  • D. 195

Solution

### Related Formula For a logarithmic term log_b(a) to be valid: a > 0, quad b > 0, quad b neq 1 ### Core Logic Analyzing the first function f_1(x) = log_5(18x - x^2 - 77): 18x - x^2 - 77 > 0 implies x^2 - 18x + 77 < 0 (x - 7)(x - 11) < 0 implies x in (7, 11) Hence, alpha = 7, beta = 11. ### Step 1: Check Second Function Base and Argument Analyzing f_2(x) = log_(x - 1)left(frac2x^2 + 3x - 2x^2 - 3x - 4right): Base constraints: x - 1 > 0 implies x > 1 x - 1 neq 1 implies x neq 2 Argument constraints: frac2x^2 + 3x - 2x^2 - 3x - 4 > 0 implies frac(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 neq 2, the common interval is: x in (4, infty) Thus, gamma = 4. ### Step 3: Calculate final sum alpha^2 + beta^2 + gamma^2 = 7^2 + 11^2 + 4^2 = 49 + 121 + 16 = 186 ### Pattern Recognition For domain intersections involving variables in both the log base and argument, always list base rules (>0, neq 1) first to eliminate invalid sign fields early on. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Mathematics: Relations and Functions

More Relations and Functions Questions — jee_main_2025_03_april_morning

Practice all Relations and Functions previous-year questions →

YOUR FIRST PREP STEP STARTS HERE

We Map Every Repeating Question in Competitive Exams.

Say goodbye to generic mock test fatigue. RankBit uses smart analysis to group past exam questions into their foundational Repeating Question Types. Find chapter weightage, track repeating questions, and score higher with targeted practice.

Select Your Target Exam

Choose an exam track below to find formulas per chapter and patterns.

Syncing Exam Intelligence

Mapping formulas and patterns across all tracks…

PATH A — FULL LENGTH PRACTICE

Full Mock Test Hub

Simulate real NTA exam conditions with fully tracked mocks. Time yourself against past papers.

Under Development
PATH B — TARGETED PRACTICE

Topic-wise Practice Hub

Practice past-year questions one chapter at a time. Pick an exam → subject → chapter and get every PYQ for that topic — pulled together from all past papers — with the chapter's key formulas alongside.

Loading Questions... Browse Topics
Latest from the Blog
View all →

Loading articles...