設(shè)點
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,若在圓
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上存在點
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,使得
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,則
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的取值范圍是( )
試題分析:依題意,直線MN與圓
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有公共點即可,即圓心
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到直線MN的距離小于等于1即可,過
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作
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MN,垂足為A,在
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中,因為
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,故
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,所以
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,則
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,解得
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.
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
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(本題滿分16分)在平面直角坐標(biāo)系
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中,已知圓
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:

,圓
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:
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
(
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,且
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為坐標(biāo)軸上的點,滿足:過點P分別作圓
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與圓
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的一條切線,切點分別為
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、
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,使得
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
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
平分圓
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與圓
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已知圓
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:
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內(nèi)有一點
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,過點
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作直線
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交圓
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于
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,
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兩點.
(1)當(dāng)
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經(jīng)過圓心
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時,求直線
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的方程;
(2)當(dāng)弦
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被點
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平分時,寫出直線
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直線
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和
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是圓

的兩條切線,若
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與
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的交點為
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,則
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與
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的夾角的正切值等于
.
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如圖,在圓
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上任取一點

,過點
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作
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軸的垂線段
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,
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為垂足.設(shè)
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為線段
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的中點.
(1)當(dāng)點
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在圓
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上運動時,求點
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的軌跡
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的方程;
(2)若圓
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在點
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處的切線與
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軸交于點
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,試判斷直線
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與軌跡

的位置關(guān)系.

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