来自黄夏旭的问题
如图,三角形ABC内接于圆O,CE⊥AB于E,交圆O于F,AD⊥BC.(1)求证:∠BAO=∠DAC.(2)求证:∠FAB=∠BAD
如图,三角形ABC内接于圆O,CE⊥AB于E,交圆O于F,AD⊥BC.(1)求证:∠BAO=∠DAC.(2)求证:∠FAB=∠BAD
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2020-12-05 06:20
如图,三角形ABC内接于圆O,CE⊥AB于E,交圆O于F,AD⊥BC.(1)求证:∠BAO=∠DAC.(2)求证:∠FAB=∠BAD
如图,三角形ABC内接于圆O,CE⊥AB于E,交圆O于F,AD⊥BC.(1)求证:∠BAO=∠DAC.(2)求证:∠FAB=∠BAD
(1)因为OA=OB所以∠BAO=∠ABO=1/2(180°-∠AOB)而∠AOB=2∠ACB所以∠BAO=∠ABO=1/2(180°-∠AOB)=90°-∠ACB因为AD⊥BC所以∠DAC=90°-∠ACB所以:∠BAO=∠DAC(2)因为CE⊥AB于E,交圆O于F,AD⊥BC.所以:∠FAB+:...