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Let R = {(1, 3), (4, 2), (2, 4), (2, 3), (3, 1)} be a relation on the set A = {1, 2, 3, 4}. Then relation R is 

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Poll Results

42.86%a function ( 3 voters )
14.29%transtive ( 1 voter )
28.57%not symmetric ( 2 voters )
14.29%reflexive ( 1 voter )
Based On 7 Votes

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In Class 12 Maths, relation refers to a connection between elements of two sets, while function is a specific type of relation where each input has exactly one output. Key concepts include domain, range, types of functions like one-one, onto, composite functions, and inverse functions.

Class 12 Maths Relations and Functions Chapter 1 for CBSE Exam 2024-25 focuses on relations between sets and types of functions like one-one and onto. It includes important concepts like domain and range of functions composite functions and inverse functions. The chapter lays a strong foundation for advanced mathematical topics in further studies.

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1 Answer

  1. We have the relation R = {(1, 3), (4, 2), (2, 4), (2, 3), (3, 1)} on the set A = {1, 2, 3, 4}.

    Definitions:
    1. Function: A relation R is a function if each element of A occurs as the first component in at most one pair of R.
    2. Transitive: A relation R is transitive if for all a, b, c ∈ A, whenever (a, b) ∈ R and (b, c) ∈ R, then (a, c) ∈ R.
    3. Symmetric: A relation R is symmetric if for all a, b ∈ A, whenever (a, b) ∈ R, then (b, a) ∈ R.
    4. Reflexive: A relation R is reflexive if for all a ∈ A, (a, a) ∈ R.

    Analysis:
    1. Is R a function?
    – The element 2 occurs as the first element in both (2, 4) and (2, 3), which goes against the definition of a function. Thus, R is not a function.

    2. Is R transitive?
    – Since (1, 3) ∈ R and (3, 1) ∈ R, we would need (1, 1) ∈ R for it to be transitive, but it isn’t there.
    – For (2, 4) ∈ R and (4, 2) ∈ R, we would need (2, 2) ∈ R, which is absent too.
    – Thus, R is not transitive.

    3. Is R symmetric?
    – Do we have (a, b) ∈ R implies (b, a) ∈ R?
    – (1, 3) ∈ R, and (3, 1) ∈ R (symmetric pair).
    – (4, 2) ∈ R, but (2, 4) ∈ R (symmetric pair).
    – All needed symmetric pairs are there. So, R is symmetric.

    4. Is R reflexive?
    – See if (a, a) ∈ R for every a ∈ A:
    – (1, 1), (2, 2), (3, 3), and (4, 4) are not in R.
    – Hence, R is not reflexive.

    Conclusion:
    The relation R is:
    – Not a function
    – Not transitive
    – Symmetric
    – Not reflexive

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