ask for help!!!!! jijing

betty_lee

ps。f(ab) = f(a)f(b), 问以下选项哪个满足此式 a)f(x)=x+1 b) f(x)= 2/x
c) f(x) = 根号x.

any tips?? thanks a lot!![em00]

tongxun

liangqi：you are a very kind person。