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
两圆\(x^{2}+y^{2}+2ax+a^{2}-4=0\)和\(x^{2}+y^{2}-4by-1+4b^{2}=0\)恰有三条公切线,若\(a∈R\),\(b∈R\),且\(ab\neq 0\),则\(\dfrac{1}{{{a}^{2}}}+\dfrac{1}{{{b}^{2}}}\)的最小值为
与圆\({{\left( x+2 \right)}^{2}}+{{(y-2)}^{2}}=1\)和圆\({{x}^{2}}+{{y}^{2}}-4x-10y+13=0\)都相切的直线的条数是 .
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 ( )
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