Gaokao Math Practice Question
已知圆 $O$ 的半径为 $1, P A$、 $P B$ 为该圆的两条切线, $A$、 $B$ 为两切点, 那么 $\overrightarrow{\mathrm{PA}} \cdot \overrightarrow{\mathrm{PB}}$ 的最小值为 ($\qquad$)
- A.$-4+\sqrt{2}$
- B.$-3+\sqrt{2}$
- C.$-4+2 \sqrt{2}$
- D.$-3+2 \sqrt{2}$
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