连接OE
△ABC∽△OEF
OE/OF=AB/AF
AB=2OE
AF=2OF
AB²+BF²=AF²
AB²+(FO+AB/2)²=4FO²
5AB²+4AB*FO-12FO²=0
(-6FO+5AB)(2FO+AB)=0
FO=5/6AB
sin∠F=OE/FO=(AB/2)/(5/6AB)=3/5
连接OE
△ABC∽△OEF
OE/OF=AB/AF
AB=2OE
AF=2OF
AB²+BF²=AF²
AB²+(FO+AB/2)²=4FO²
5AB²+4AB*FO-12FO²=0
(-6FO+5AB)(2FO+AB)=0
FO=5/6AB
sin∠F=OE/FO=(AB/2)/(5/6AB)=3/5