优优班--学霸训练营 > 知识点挑题
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            • 1.
              由直线\(y=x+1\)上的一点向圆\((x-3)^{2}+y^{2}=1\)引切线,则切线长的最小值为\((\)  \()\)
              A.\(1\)
              B.\(2 \sqrt {2}\)
              C.\( \sqrt {7}\)
              D.\(3\)
            • 2.
              已知圆\(M\)的半径为\(4\),圆心在\(x\)轴的负半轴上,直线\(3x+4y+4=0\)与圆\(M\)相切,则圆\(M\)的方程为\((\)  \()\)
              A.\((x+8)^{2}+y^{2}=16\)
              B.\((x- \dfrac {16}{3})^{2}+y^{2}=16\)
              C.\((x-8)^{2}+y^{2}=16\)
              D.\((x+ \dfrac {16}{3})^{2}+y^{2}=16)\)
            • 3.
              过直线\(y=2x+3\)上的点作圆\(x^{2}+y^{2}-4x+6y+12=0\)的切线,则切线长的最小值为\((\)  \()\)
              A.\( \sqrt {19}\)
              B.\(2 \sqrt {5}\)
              C.\( \sqrt {21}\)
              D.\( \dfrac { \sqrt {55}}{5}\)
            • 4.
              已知双曲线\(C: \dfrac {x^{2}}{a^{2}}- \dfrac {y^{2}}{b^{2}}=1(a > 0,b > 0)\)的左、右焦点分别为\(F_{1}\)、\(F_{2}\),以\(F_{2}\)为圆心的圆与双曲线\(C\)在第一象限交于点\(P\),直线\(PF_{1}\)恰与圆\(F_{2}\)相切于点\(P\),与双曲线左支交于点\(Q\),且\(|PQ|=2|F_{1}Q|\),则双曲线的离心率为\((\)  \()\)
              A.\( \sqrt {3}\)
              B.\( \sqrt {5}\)
              C.\( \sqrt {13}\)
              D.\( \sqrt {15}\)
            • 5. 直线\(3x+4y=b\)与圆\(x^{2}+y^{2}-2x-2y+1=0\)相切,则\(b=(\)  \()\)
              A.\(-2\)或\(12\)
              B.\(2\)或\(-12\)
              C.\(-2\)或\(-12\)
              D.\(2\)或\(12\)
            • 6.
              过\((2,3)\)点作圆\((x-1)^{2}+(y-1)^{2}=1\)的切线,所得切线方程为\((\)  \()\)
              A.\(x-2=0\)和\(4x-3y+1=0\)
              B.\(y-2=0\)和\(4x-3y+1=0\)
              C.\(x-2=0\)和\(3x-4y+6=0\)
              D.\(y-2=0\)和\(3x-4y+6=0\)
            • 7.
              直线\(l\)经过点\(P(-3,4)\)且与圆\(x^{2}+y^{2}=25\)相切,则直线\(l\)的方程是\((\)  \()\)
              A.\(y-4=- \dfrac {4}{3}(x+3)\)
              B.\(y-4= \dfrac {3}{4}(x+3)\)
              C.\(y+4=- \dfrac {4}{3}(x-3)\)
              D.\(y+4= \dfrac {3}{4}(x-3)\)
            • 8.
              如图,圆\(C\)分别与\(x\)轴正半轴,\(y\)轴正半轴相切于点\(A\),\(B\),过劣弧\( \overparen {AB}\)上一点\(T\)作圆\(C\)的切线,分别交\(x\)轴正半轴,\(y\)轴正半轴于点\(M\),\(N\),若点\(Q(2,1)\)是切线上一点,则\(\triangle MON\)周长的最小值为\((\)  \()\)
              A.\(10\)
              B.\(8\)
              C.\(4 \sqrt {5}\)
              D.\(12\)
            • 9.
              若直线\(x+y+m=0\)与圆\(x^{2}+y^{2}=m\)相切,则\(m\)的值是\((\)  \()\)
              A.\(0\)或\(2\)
              B.\(2\)
              C.\( \sqrt {2}\)
              D.\( \sqrt {2}\)或\(2\)
            • 10.
              已知\(⊙C\):\(x^{2}+y^{2}=1\),对\(A(0,-2)\),\(B(a,2)\),从点\(A\)观察点\(B\),要使视线不被\(⊙C\)挡住,则实数\(a\)的取值范围是\((\)  \()\)
              A.\((-∞,-2)∪(2,+∞)\)
              B.\((-∞,- \dfrac {4 \sqrt {3}}{3})∪( \dfrac {4 \sqrt {3}}{3},+∞)\)
              C.\((-∞,- \dfrac {2 \sqrt {3}}{3})∪( \dfrac {2 \sqrt {3}}{3},+∞)\)
              D.\((- \dfrac {4 \sqrt {3}}{3}, \dfrac {4 \sqrt {3}}{3})\)
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