If R is a relation on the set {1, 2, 3, 4} defined by R = {(1, 1), (2, 2), (3, 3
Practice Questions
Q1
If R is a relation on the set {1, 2, 3, 4} defined by R = {(1, 1), (2, 2), (3, 3), (4, 4), (1, 2), (2, 1)}, what type of relation is R?
Reflexive
Symmetric
Transitive
Both reflexive and symmetric
Questions & Step-by-Step Solutions
If R is a relation on the set {1, 2, 3, 4} defined by R = {(1, 1), (2, 2), (3, 3), (4, 4), (1, 2), (2, 1)}, what type of relation is R?
Step 1: Identify the set we are working with, which is {1, 2, 3, 4}.
Step 2: Look at the relation R, which is defined as R = {(1, 1), (2, 2), (3, 3), (4, 4), (1, 2), (2, 1)}.
Step 3: Check if R is reflexive. A relation is reflexive if it contains all pairs (a, a) for every element a in the set. Here, we have (1, 1), (2, 2), (3, 3), and (4, 4), which means R is reflexive.
Step 4: Check if R is symmetric. A relation is symmetric if for every pair (a, b) in R, the pair (b, a) is also in R. We see (1, 2) is in R, and (2, 1) is also in R, so R is symmetric.
Step 5: Conclude that R is both reflexive and symmetric.
Reflexive Relation – A relation R on a set is reflexive if every element is related to itself, meaning for every a in the set, (a, a) is in R.
Symmetric Relation – A relation R is symmetric if for every (a, b) in R, the pair (b, a) is also in R.