csat-suneung 2018 Q27
4 marks
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As shown in the figure, for a point P on the hyperbola $\frac { x ^ { 2 } } { 8 } - \frac { y ^ { 2 } } { 17 } = 1$ with foci $\mathrm { F } , \mathrm { F } ^ { \prime }$, there is a circle $C$ that is tangent to both line FP and line $\mathrm { F } ^ { \prime } \mathrm { P }$ simultaneously and has its center on the $y$-axis. For point Q, the point of tangency of line $\mathrm { F } ^ { \prime } \mathrm { P }$ with circle $C$, we have $\overline { \mathrm { F } ^ { \prime } \mathrm { Q } } = 5 \sqrt { 2 }$. Find the value of $\overline { \mathrm { FP } } ^ { 2 } + { \overline { \mathrm { F } ^ { \prime } \mathrm { P } } } ^ { 2 }$. (Here, $\overline { \mathrm { F } ^ { \prime } \mathrm { P } } < \overline { \mathrm { FP } }$) [4 points]