Question
Let I denote the interval [0,oo). For each r ∈ I, define
A={(x,y)∈ RxR:x^2+y^2=r^2}
B={(x,y)∈ RxR:x^2+y^2<=r^2}
C={(x,y)∈ RxR:x^2+y^2<r^2}
Determine
UA and ∩A
UB and ∩B
UC and ∩C
A={(x,y)∈ RxR:x^2+y^2=r^2}
B={(x,y)∈ RxR:x^2+y^2<=r^2}
C={(x,y)∈ RxR:x^2+y^2<r^2}
Determine
UA and ∩A
UB and ∩B
UC and ∩C