Question

If $R=\left\{\right(x,y):x,y\in Z,x^2+y^2\le 4\}$ is a relation in $Z$ then domain $D$ is

• A. $\{-2,-1,0,1,2\}$
• B. $\{-2,-1,0\}$
• C. $\{0,1,2\}$
• D. None of these

Answer 1

Answer: (A)

$\{-2,-1,0,1,2\}$

Relation $Z$ consists of all the integral points inside and on the circle of radius $2$ and center $(0,0)$.

For all the points $(x,y)$ which lie inside and on the circle $xϵ[-2,2]$ and $yϵ[-2,2]$. Hence the domain is the integer values of $x$ i.e $-2,-1,0,1,2.$