共50条信息
已知:如图,在\(\triangle ABC\)中,\(AB=AC\),以\(AC\)为直径作\(⊙O\)交\(BC\)于点\(D\),过点\(D\)作\(⊙O\)的切线交\(AB\)于点\(E\),交\(AC\)的延长线于点\(F\).
\((1)\)求证:\(DE⊥AB\);
\((2)\)若\(\tan ∠BDE= \dfrac{1}{2} \), \(CF=3\),求\(DF\)的长.
如图,在\(\triangle ABC\)中, \(AB=AC\),\(BD⊥AC\)于点\(D.AC=10\),\(\cos A=\dfrac{4}{5}\),求\(BC\)的长.
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