过点F(0,1)作直线l与抛物线x
2=4y相交于两点A、B,圆C:x
2+(y+1)
2=1
(1)若抛物线在点B处的切线恰好与圆C相切,求直线l的方程;
(2)过点A、B分别作圆C的切线BD、AE,试求|AB|
2-|AE|
2-|BD|
2的取值范围.
考点分析:
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