共50条信息
如图,已知\(⊙O\)的直径\(AB=6\),\(E\)、\(F\)为\(AB\)的三等分点,\(M\)、\(N\)为\(\overset\frown{AB}\)上两点,且\(∠MEB=∠NFB=60^{\circ}\),则\(EM+FN= \) .
如图,\(AB\)是\(⊙O\)的直径,点\(C\)在\(AB\)的延长线上,\(CD\)与\(⊙O\)相切于点\(D\),\(CE⊥AD\),垂足为点\(E\).
\((1)\)求证:\(∠A=∠BDC\);
\((2)\)若\(DE=2\),\(∠DCE=30^{\circ}\),求图中阴影部分的面积.
已知:如图,在\(\vartriangle ABC\)中,\(AB=AC\),\(AE\)是角平分线,\(BM\)平分\(\angle ABC\)交\(AE\)于点\(M\),经过两点的\(\odot O\)交\(BC\)于点\(G\),交\(AB\)于点\(F\),\(FB\)恰为\(\odot O\)的直径.
\((1)\)求证:\(AE\)与\(\odot O\)相切;
\((2)\)当\(BC=4,\cos C= \dfrac{1}{3} \)时,求\(\odot O\)的半径。
如图,\(Rt\triangle \)\(ABC\)中,\(∠\)\(C\)\(=90^{\circ}\),\(\tan B=\dfrac{4}{3}\),点\(D\)、\(E\)分别在边\(AC\)、\(BC\)上,且\(CD\cdot CB=CA\cdot CE\).
\((1)\)求证:\(DE\)\(/\!/\)\(AB\);
\((2)\)若\(CD\)\(=\dfrac{32}{5}\),\(BE\)\(=5\),求证:\(AB\)与\(\triangle \)\(CDE\)的外接圆相切.
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