The relation R on the set of real numbers defined by \(R= \{(a,b): a\le b^2\}\) is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → neither reflexive nor symmetric nor transitive
One counterexample is enough to rule out each property.
Reflexive needs \(a \le a^2\) for every real a. Take \(a = \frac{1}{2}\):
\( \displaystyle \frac{1}{2} \le \frac{1}{4} \) is false.
So \(\left(\frac{1}{2}, \frac{1}{2}\right) \notin R\): R is not reflexive.
Symmetric fails for the pair (1, 2):
\((1, 2) \in R\) since \(1 \le 2^2 = 4\)
\((2, 1) \notin R\) since \(2 \le 1^2 = 1\) is false
Transitive fails for 4, −2, 1:
\((4, -2) \in R\) since \(4 \le (-2)^2 = 4\)
\((-2, 1) \in R\) since \(-2 \le 1^2 = 1\)
\((4, 1) \notin R\) since \(4 \le 1^2 = 1\) is false
So R is neither reflexive nor symmetric nor transitive.
NCERT (2026-27 edition):
Types of Relations
