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The relation R on the set of real numbers defined by R={(a,b):a≤b2}R = \{(a, b): a \leq b^2\} is

Solution

✅ Correct Option: 1

The relation R on the set of real numbers is defined as R={(a,b):a≤b2}R = \{(a, b): a \leq b^2\}.

Two numbers aa and bb are related if aa is less than or equal to bb squared.


A relation is reflexive if (a,a)∈R(a, a) \in R for all real numbers aa.

For the relation R, this requires a≤a2a \leq a^2 to be true for all real numbers.

Testing with a=0.5a = 0.5:

0.5≤(0.5)20.5 \leq (0.5)^2

0.5≤0.250.5 \leq 0.25

This is false.

The relation is not reflexive.


A relation is symmetric if whenever (a,b)∈R(a, b) \in R, then (b,a)∈R(b, a) \in R.

For the relation R, if a≤b2a \leq b^2, then b≤a2b \leq a^2 must also be true.

Testing with a=1a = 1 and b=2b = 2:

Check (1,2)(1, 2): 1≤22=41 \leq 2^2 = 4 is true.

Check (2,1)(2, 1): 2≤12=12 \leq 1^2 = 1 is false.

Since (1,2)∈R(1, 2) \in R but (2,1)∉R(2, 1) \notin R, the relation is not symmetric.


A relation is transitive if whenever (a,b)∈R(a, b) \in R and (b,c)∈R(b, c) \in R, then (a,c)∈R(a, c) \in R.

For the relation R, if a≤b2a \leq b^2 and b≤c2b \leq c^2, then a≤c2a \leq c^2 must be true.

Testing with a=4a = 4, b=−2b = -2, c=1c = 1:

Check (4,−2)(4, -2): 4≤(−2)2=44 \leq (-2)^2 = 4 is true.

Check (−2,1)(-2, 1): −2≤12=1-2 \leq 1^2 = 1 is true.

Check (4,1)(4, 1): 4≤12=14 \leq 1^2 = 1 is false.

Since (4,−2)∈R(4, -2) \in R and (−2,1)∈R(-2, 1) \in R, but (4,1)∉R(4, 1) \notin R, the relation is not transitive.


The relation R is neither reflexive nor symmetric nor transitive.

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