Let R1
and R2
be two relation defined as
follows :
R1
= {(a, b) $\in$ R2
: a2
+ b2 $\in$ Q} and
R2
= {(a, b) $\in$ R2
: a2
+ b2 $\notin$ Q},
where Q is the
set of all rational numbers. Then :
Solution
For R<sub>1</sub> :<br><br>Let a = 1 + $\sqrt 2$, b = 1 $-$ $\sqrt 2$, c = ${8^{{1 \over 4}}}$<br><br>aR<sub>1</sub>b : a<sup>2</sup> + b<sup>2</sup> = 6 $\in$ Q<br><br>bR<sub>1</sub>c : b<sup>2</sup> + c<sup>2</sup> = 3 $-$ 2$\sqrt 2$ + 2$\sqrt 2$ = 3 $\in$ Q<br><br>aR<sub>1</sub>c : a<sup>2</sup> + c<sup>2</sup> = 3 + 2$\sqrt 2$ + 2$\sqrt 2$ $\notin$ Q<br><br>$\therefore$ R<sub>1</sub> is not transitive.<br><br>For R<sub>2</sub> : <br><br>Let a = 1 + $\sqrt 2$, b = $\sqrt 2$, c = 1 $-$ $\sqrt 2$<br><br>aR<sub>2</sub>b : a<sup>2</sup> + b<sup>2</sup> = 5 + 2$\sqrt 2$ $\notin$ Q<br><br>bR<sub>2</sub>c : b<sup>2</sup> + c<sup>2</sup> = 5 $-$ 2$\sqrt 2$ $\notin$ Q<br><br>aR<sub>2</sub>c : a<sup>2</sup> + c<sup>2</sup> = 3 + 2$\sqrt 2$ + 3 $-$ 2$\sqrt 2$ = 6 $\in$ Q<br><br>$\therefore$ R<sub>2</sub> is not transitive.
About this question
Subject: Mathematics · Chapter: Sets, Relations and Functions · Topic: Sets and Operations
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