The centres of a set of circles, each of radius 3, lie on the circle x2+y2=25. The locus of any point in the set is:
Solutions · 1
Official solution
For any point P(x,y) in the given circle,
we should have
\[OA \le OP \le OB\]
\[ \Rightarrow \left( {5 - 3} \right) \le \sqrt {{x^2} + {y^2}} \le 5 + 3\]
\[ \Rightarrow 4 \le {x^2} + {y^2} \le 64\]