共50条信息
圆\(C_{1}\)：\((x+1)^{2}+(y+2)^{2}=4\)与圆\(C_{2}\)：\((x-1)^{2}+(y+1)^{2}=9\)有\((\) \()\)条公切线
在坐标平面内，与点\(A(1,2)\)的距离为\(1\)，且与点\(B(5,5)\)的距离为\(d\)的直线共有\(4\)条，则\(d\)的取值范围是 ( )
两圆\((x{-}2)^{2}{+}(y{-}1)^{2}{=}4\)与\((x{+}1)^{2}{+}(y{-}2)^{2}{=}9\)的公切线有\(({ })\)条\(.\)
两圆\((x-2)^{2}+(y-1)^{2}=4\)与\((x+1)^{2}+(y-2)^{2}=9\)的公切线有\((\) \()\)
圆\({{(x+2)}^{2}}+{{y}^{2}}=4\)与圆\({{(x-2)}^{2}}+{{(y-1)}^{2}}=9\)的公切线的条数为( )
圆\({{x}^{2}}+{{y}^{2}}-2x+4y-4=0\)与\({{x}^{2}}+{{y}^{2}}+4x-4y-56=0\)的公切线条数为\((\) \()\)
圆：\({x}^{2}+{y}^{2}+2ax+{a}^{2}-9=0 \)和圆：\({x}^{2}+{y}^{2}-4by-1+4{b}^{2}=0 \)只有一条公切线，若\(a∈R \)，\(b∈R \)，且\(a\ne 0\)，则\(\dfrac{4}{{{a}^{2}}}+\dfrac{1}{{{b}^{2}}+1}\)的最小值为\((\) \()\)
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