Let A be the set of all functions fcolon mathbbZ to mathbbZ and R be a relation on A such that R = \(f, g): f(0) = g(1) text and f(1) = g(0)\. Then R is:

Solution & Explanation

### Related Formula Definition of properties of binary relations: * Reflexive: (f, f) in R iff f(0) = f(1) * Symmetric: (f, g) in R implies (g, f) in R * Transitive: (f, g) in R text and (g, h) in R implies (f, h) in R ### Core Logic Evaluate reflexivity, symmetry, and transitivity sequentially by plugging standard arbitrary function values into the condition definition. ### Step 1: Reflexivity Audit For (f,f) in R, we require f(0) = f(1) and f(1) = f(0). This holds true only for functions whose values at 0 and 1 are identical. Since it does not hold true for *all* possible functions mapping mathbbZ to mathbbZ (e.g., f(x)=x), R is **not reflexive**. ### Step 2: Symmetry Audit Assume (f,g) in R implies f(0) = g(1) and f(1) = g(0). To check if (g,f) in R, check its matching constraints: g(0) = f(1) and g(1) = f(0). Both statements are perfectly identical to our assumption. Therefore, R is **symmetric**. ### Step 3: Transitivity Audit Assume (f,g) in R implies f(0) = g(1), f(1) = g(0). Assume (g,h) in R implies g(0) = h(1), g(1) = h(0). For (f,h) in R, we need f(0) = h(1) and f(1) = h(0). From assumptions: f(0) = g(1) = h(0) and f(1) = g(0) = h(1). This means f(0) = h(0) and f(1) = h(1), which does *not* necessarily satisfy f(0)=h(1). Hence, R is **not transitive**. ### Pattern Recognition The relation swaps indices 0 and 1. Swapping twice returns you to the original position, which visually justifies why symmetry holds trivially, while transitivity creates a cyclic dependency that fails standard property constraints. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Mathematics: Relations and Functions

More Relations and Functions Previous-Year Questions — Page 10

Q6 jee_main_2024_31_jan_morning Composition of Functions
If f(x) = frac4x + 36x - 4, x neq frac23 and (fof)(x) = g(x), where g : mathbbR - left\frac23right\ to mathbbR - left\frac23right\, then (gogog)(4) is equal to
  • A. -frac1920
  • B. frac1920
  • C. -4
  • D. 4

Solution

### Core Logic f(x) = frac4x + 36x - 4 Compute g(x) = f(f(x)): g(x) = frac4left(frac4x + 36x - 4right) + 36left(frac4x + 36x - 4right) - 4 = frac16x + 12 + 18x - 1224x + 18 - 24x + 16 = frac34x34 = x ### Step 1: Composition Evaluation Since g(x) = x, g is the identity function. (gogog)(4) = g(g(g(4))) = 4 ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Maths: Relations and Functions
Q29 jee_main_2024_31_jan_morning Equivalence Relations
Let A = \1, 2, 3, 4\ and R = \(1, 2), (2, 3), (1, 4)\ be a relation on A. Let S be the equivalence relation on A such that R subset S and the number of elements in S is n. Then, the minimum value of n is
Numerical Answer. Answer: 16 to 16

Solution

### Core Logic S must be reflexive, symmetric, and transitive, containing (1,2), (2,3), and (1,4). Symmetric property forces (2,1), (3,2), (4,1) in S. Transitive property: (1,2) and (2,3) implies (1,3) in S. Symmetric implies (3,1) in S. (4,1) and (1,2) implies (4,2) in S. Symmetric implies (2,4) in S. (4,1) and (1,3) implies (4,3) in S. Symmetric implies (3,4) in S. ### Step 1: Universal Relation Since 1 is related to 2, 3, 4 and the relation is an equivalence relation (which creates partitions), all elements 1, 2, 3, and 4 must fall into the same single equivalence class. Thus, S must contain all possible ordered pairs in A times A. ### Step 2: Final Count Number of elements in A times A = 4 times 4 = 16. Minimum value of n is 16. ### Pattern Recognition If a relation connects all elements in a set to each other through a chain, its equivalence closure is the universal relation A times A. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Maths: Relations and Functions
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