题目如图,已知ABABAB为⊙O\odot O⊙O的直径,过⊙O\odot O⊙O上点CCC的切线交ABABAB的延长线于点EEE,AD⊥ECAD\bot ECAD⊥EC于点DDD.且交⊙O\odot O⊙O于点FFF,连接BCBCBC,CFCFCF,ACACAC.(1)(1)(1)求证:BC=CFBC=CFBC=CF;(2)(2)(2)若AD=3AD=3AD=3,DE=4DE=4DE=4,求BEBEBE的长.知识点:切线长定理章节:图形的性质 / 圆