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A relation R on the set A={1,2,3,…,13,14}A = \{1, 2, 3, \ldots, 13, 14\} defined as R={(x,y):3x−y=0}R = \{(x,y): 3x - y = 0\} is

Solution

✅ Correct Option: 4

The set A={1,2,3,…,13,14}A = \{1, 2, 3, \ldots, 13, 14\}

The relation R={(x,y):3x−y=0}R = \{(x,y): 3x - y = 0\}

This means y=3xy = 3x

A pair (x,y)(x,y) is in relation RR only if the second number is exactly 3 times the first number.


Finding which pairs from set AA satisfy y=3xy = 3x:

When x=1x = 1: y=3(1)=3y = 3(1) = 3 → (1,3)∈R(1,3) \in R

When x=2x = 2: y=3(2)=6y = 3(2) = 6 → (2,6)∈R(2,6) \in R

When x=3x = 3: y=3(3)=9y = 3(3) = 9 → (3,9)∈R(3,9) \in R

When x=4x = 4: y=3(4)=12y = 3(4) = 12 → (4,12)∈R(4,12) \in R

When x=5x = 5: y=3(5)=15y = 3(5) = 15 (15 is not in set AA)

Therefore, R={(1,3),(2,6),(3,9),(4,12)}R = \{(1,3), (2,6), (3,9), (4,12)\}


A relation is reflexive if (x,x)∈R(x,x) \in R for all x∈Ax \in A.

For (x,x)(x,x) to be in RR:

3x−x=03x - x = 0

2x=02x = 0

x=0x = 0

Since 0∉A0 \notin A, no element like (1,1),(2,2),(3,3),…(1,1), (2,2), (3,3), \ldots is in RR.

The relation is not reflexive.


A relation is symmetric if (x,y)∈R(x,y) \in R implies (y,x)∈R(y,x) \in R.

Consider (1,3)∈R(1,3) \in R. For symmetry, (3,1)(3,1) should also be in RR.

Check: 3(3)−1=9−1=8≠03(3) - 1 = 9 - 1 = 8 \neq 0

So (3,1)∉R(3,1) \notin R.

The relation is not symmetric.


A relation is transitive if (x,y)∈R(x,y) \in R and (y,z)∈R(y,z) \in R implies (x,z)∈R(x,z) \in R.

Consider (1,3)∈R(1,3) \in R and (3,9)∈R(3,9) \in R. For transitivity, (1,9)(1,9) should also be in RR.

Check: 3(1)−9=3−9=−6≠03(1) - 9 = 3 - 9 = -6 \neq 0

So (1,9)∉R(1,9) \notin R.

The relation is not transitive.


The relation RR is neither reflexive nor symmetric nor transitive.

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