Trong không gian với hệ tọa độ Oxyz, cho mặt cầu (S)...

Gọi \)">A(0;m;0)\overrightarrow{OA}\left\{ \begin{aligned}
& x=X \\
& y=Y+m \\
& z=Z \\
\end{aligned} \right.\left( S \right):{{X}^{2}}+{{\left( Y+m-4 \right)}^{2}}+{{Z}^{2}}=5I\left( 0;m-4;0 \right)R=\sqrt{5}\begin{aligned}
& d\left( I,\left( AXY \right) \right)={{d}_{1}}=0\Rightarrow {{r}_{1}}=\sqrt{5} \\
& d\left( I,\left( AYZ \right) \right)={{d}_{2}}=\left| m-4 \right|\Rightarrow {{r}_{2}}=\sqrt{5-{{(m-4)}^{2}}} \\
& d\left( I,\left( AZX \right) \right)=0\Rightarrow {{r}_{3}}=\sqrt{5} \\
\end{aligned}\left( r_{1}^{2}+r_{2}^{2}+r_{3}^{2} \right)\pi =11\pi \Rightarrow r_{1}^{2}+r_{2}^{2}+r_{3}^{2}=11\Leftrightarrow 15-{{(m-4)}^{2}}=11\Leftrightarrow \left[ \begin{aligned}
& m=6 \\
& m=2 \\
\end{aligned} \right.\left[ \begin{aligned}
& A(0;2;0) \\
& A(0;6;0) \\
\end{aligned} \right.$ cần tìm.