优优班--学霸训练营 > 知识点挑题
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            • 1.

              已知\(A\),\(B\)是圆\(O:x^{2}+y^{2}=16\)上的两个动点,且\(|AB|=4\),\(\overrightarrow{OC}=\dfrac{{5}}{{3}}\overrightarrow{OA}-\dfrac{{2}}{{3}}\overrightarrow{OB}\),若\(M\)是线段\(AB\)的中点,则\(\overrightarrow{OC}\cdot \overrightarrow{OM}=\)

              A.\({8}+{4}\sqrt{{3}}\)
              B.\({8}-{4}\sqrt{{3}}\)
              C.\(12\)
              D.\(4\)
            • 2.

              已知直线\(3x+4y-15=0\)与圆\(O\):\(x^{2}+y^{2}=25\)交于\(A\),\(B\)两点,点\(C\)在圆\(O\)上,且\(S_{\triangle ABC}=8\),则满足条件的点\(C\)的个数为\((\)  \()\)

              A.\(1\)                                               
              B.\(2\)

              C.\(3\)                                                
              D.\(4\)
            • 3.

              若\(P(2,-1)\)为圆\(O:\begin{cases}x=1+5\cos θ \\ y=5\sin θ\end{cases}\left(o\leqslant θ < 2π\right) \)的弦的中点,则该弦所在直线\(l\)的方程是

              A.\(x-y-3=0\)
              B.\(x+2y=0\)
              C.\(x+y-1=0\)
              D.\(2x-y-5=0\)
            • 4.

              直线\(y=kx+3\)与圆\((x-3)^{2}+(y-2)^{2}=4\)相交于\(M\),\(N\)两点,若\(|MN|\geqslant 2\sqrt{3}\),则实数\(k\)的取值范围是\((\)    \()\)

              A.\(\left[ -\dfrac{3}{4},0 \right]\)
              B.\((−∞,− \dfrac{3}{4})∪[0,+∞) \)
              C.\(\left[ -\dfrac{\sqrt{3}}{3},\dfrac{\sqrt{3}}{3} \right]\)
              D.\(\left[ -\dfrac{2}{3},0 \right]\)
            • 5.

              联立两相交圆的方程,并消掉二次项后得到的二元一次方程是两圆的公共弦所在的直线方程\(.\)(    )

              A.正确
              B.错误
            • 6.

              已知直线\(y=kx+3\)与圆\((x-2)^{2}+(y-3)^{2}=4\)相交于\(M\),\(N\)两点,若\(|MN|\geqslant 2\sqrt{3}\),则\(k\)的取值范围是  \((\)    \()\)

              A.\((-∞,- \dfrac{ \sqrt{3}}{3}]∪[ \dfrac{ \sqrt{3}}{3},+∞) \)
              B.\([- \dfrac{ \sqrt{3}}{3}, \dfrac{ \sqrt{3}}{3}] \)
              C.\((-∞,- \dfrac{ \sqrt{3}}{2}]∪[ \dfrac{ \sqrt{3}}{2},+∞) \)
              D.\([- \dfrac{ \sqrt{3}}{2}, \dfrac{ \sqrt{3}}{2}] \)
            • 7.

              直线\(y{=}kx{+}3\)与圆\((x{-}2)^{2}{+}(y{-}3)^{2}{=}4\)相交于\(M\),\(N\)两点,若\({|}MN{|} \geqslant 2\),则\(k\)的取值范围是\((\)  \()\)

              A.\(\ {[-}\dfrac{2}{3}{,}0{]}\)
              B.\(({-∞,-}\sqrt{3}{]∪[}\sqrt{3}{,+∞})\)
              C.\({[-}\dfrac{\sqrt{3}}{3}{,}\dfrac{\sqrt{3}}{3}{]}\)
              D.\({[-}\sqrt{3}{,}\sqrt{3}{]}\)
            • 8.

              直线\(\ell \):\(kx+y+4=0(k∈R)\)是圆\(C\):\(x^{2}+y^{2}+4x-4y+6=0\)的一条对称轴,过点\(A(0,k)\)作斜率为\(1\)的直线\(m\),则直线\(m\)被圆\(C\)所截得的弦长为\((\)  \()\)

              A.\(\dfrac{ \sqrt{2}}{2} \)
              B.\(\sqrt{2} \)
              C.\(\sqrt{6} \)
              D.\(2\sqrt{6} \)
            • 9.

              已知\(x\),\(y\)满足约束条件\(\begin{cases} & x+y-2\leqslant 0, \\ & x-2y-2\leqslant 0, \\ & 2x-y+2\geqslant 0, \\ \end{cases}\)且\(b=-2x-y\),当\(b\)取得最大值时,直线\(2x+y+b=0\)被圆\((x-1)^{2}+(y-2)^{2}=25\)截得的弦长为

              A.\(10\)   
              B.\(2\sqrt{5}\)
              C.\(3\sqrt{5}\)
              D.\(4\sqrt{5}\)
            • 10.

              若\(a\),\(b\)是正数,直线\(2ax+by-2=0\)被圆\(x^{2}+y^{2}=4\)截得的弦长为\(2\sqrt{3}\),则\(t=a\sqrt{1+2{{b}^{2}}}\)取得最大值时\(a\)的值为

              A.\(\dfrac{1}{2}\)
              B.\(\dfrac{\sqrt{3}}{2}\)
              C.\(\dfrac{\sqrt{3}}{4}\)
              D.\(\dfrac{3}{4}\)
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