108竹北高中代理

填充9.
已知\(O\)為原點，\(A,B\)為橢圓\(\displaystyle \frac{x^2}{25}+\frac{y^2}{16}=1\)上兩點，且\(\overline{OA}⊥\overline{OB}\)，則\(\displaystyle \frac{1}{\overline{OA}^2}+\frac{1}{\overline{OB}^2}=\)　　　.

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