老师 有时间帮看一下
1个回答

作图过程省略了

(1)

|AA1|=|AF|,|BB1|=BF|

∴∠AA1F=∠AFA1=1/2*∠A1AF

∠BB1F=∠BFB1=1/2*∠B1BF

∴∠AFA1+∠BFB1=1/2(∠A1AF+∠B1BF)

∵∠A1AF+∠B1BF=180º

∴∠AFA1+∠BFB1=90º

∴∠A1FB1=90º

设M1为A1B1中点,

∴MA1=M1F

∴∠M1FA1=∠M1A1F

∴∠M1FA=∠M1FA1+∠A1FA

=∠M1A1F+∠FA1A=90

即M1F⊥AB

以A1B1为直径的圆与AB相切,切点为F

(2)

令A1F交y轴于C点,

易知ΔA1A0C≌ΔFOC

∴OA0与A1F平分于C

做CD⊥AF,垂足为D

∵|AA1|=|AF|

∴C到AA1以及AF的距离相等

即|CA0|=|CD|

∴以OA0为直径的圆与AF相切.