The center of circle C1 is O1(0,0) and its radius is r1=r.
The center of circle C2 is O2(3,4) and its radius is r2=5.
The distance between the centers of the two circles is d=32+42=5.
Since C2 lies entirely within C1, the minimum distance between a point on C1 and a point on C2 is given by r1−(d+r2).
We are given that min∣z1−z2∣=2.
r−(5+5)=2⇒r−10=2⇒r=12
The maximum distance between a point on C1 and a point on C2 is given by r1+d+r2.
max∣z1−z2∣=12+5+5=22
Answer: 22