因为f(1/3)=1,所以f(1/3)+f(1/3)=2
因为f(xy)=f(x)+f(y),所以f[(1/3)*(1/3)]=f(1/9)=2
f(x)+f(2-x)=f[x(2-x)]0,所以
x(2-x)>1/9
1-2根号2/3