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
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.
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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