Question:
If R is a relation defined on the set Z of integers by the rule (x, y) ∈ R ⇔ x2 + y2 = 9, then write domain of R.
Solution:
We need to find (x, y) ∈ R such that x2 + y2 = 9.
Now,
$(3)^{2}+0^{2}=9$
$\Rightarrow(-3)^{2}+0^{2}=9$
$x$ can take values $-3,0$ and $3 .$
$\therefore$ Domain $(R)=\{-3,0,3\}$