共50条信息
已知直线\(l\):\(x+ay-1=0(a∈R)\)是圆\(C\):\(x^{2}+y^{2}-4x-2y+1=0\)的对称轴,过点\(A(-4,a)\)作圆\(C\)的一条切线,切点为\(B\),则\(|AB|\)等于\((\) \()\)
已知点\(P( \sqrt{2}+1,2- \sqrt{2})\),点\(M(3,1)\),圆\(C\):\((x-1)^{2}+(y-2)^{2}=4\).
\((1)\)求过点\(P\)的圆\(C\)的切线方程;
\((2)\)求过点\(M\)的圆\(C\)的切线方程,并求出切线长.
已知圆\(C:{x}^{2}+{y}^{2}-4x-6y+12=0 \),点\(A\left(3,5\right) \),求:
\((1)\)过点\(A\)的圆的切线方程;
\((2)O\)点是坐标原点,连接\(OA,OC \),求\(∆AOC \)的面积\(S\).
\(20.\)已知圆\(M\)过两点\(C\)\((1,-1)\),\(D\)\((-1,1)\),且圆心\(M\)在\(x\)\(+\)\(y\)\(-2=0\)上.
\((1)\)求圆\(M\)的方程;
\((2)\)设\(P\)是直线\(3\)\(x\)\(+4\)\(y\)\(+8=0\)上的动点,\(PA\),\(PB\)是圆\(M\)的两条切线,\(A\),\(B\)为切点,求四边形\(PAMB\)面积的最小值.
在平面直角坐标系\(xOy\)中,点\(P\)是直线\(l:x=-\dfrac{1}{2}\)上一动点,定点\(F(\dfrac{1}{2},0)\),点\(Q\)为\(PF\)的中点,动点\(M\)满足\(\overrightarrow{MQ}\cdot \overrightarrow{PF}=0\),\(\overrightarrow{MP}=\lambda \overrightarrow{OF}(\lambda \in R)\),过点\(M\)作圆\((x-3)^{2}+y^{2}=2\)的切线,切点分别为\(S\),\(T\),则\(\overrightarrow{MS}\cdot \overrightarrow{MT}\)的最小值是
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