If the sets A and B are defined as
A={(x,y)∣y=1/x,x≠0,x∈R}
B={(x,y)∣y=−x,x∈R,} Then
A∩B=A
A∩B=B
A∩B=ϕ
A∪B=A
For, A∩B we have
−x=1x
⇒ −x2=1
⇒ x2=−1, which is not possible
∴ A∩B=ϕ