If R=(x,y)x,y∈z,x^2+y^2≤4 is a relation in Z, then domain of R is:

$∵R=\{(x,y)x,y∈z,x^2+y^2≤4\}$ 

$∴R=\{(-2,0),(-1,0),(-1,1),(0,-1),(0,1),(0,2),(0,-2),(1,0),(1,1),(2,0)\}$

Hence, domain of {-2, -1, 0, 1, 2}