1.令x=y=0,f(0+0)=f(0)^2,f(0)=0或1
令x=0,y=1,则f(1)=f(0)*f(1)=2,∴f(0)≠0 ∴f(0)=1
2.在R上任取x1
f(x2) = f[x1+x2-x1] = f(x1)*f(x2-x1)
f[x1]/f[x2]=1/f[x1-x2]<1
f(x1)
3. f(1)=2 2f(1)=4 f(1)*f(1)=2f(1)=4 f(2)=4
原不等式变形为f(3x-x^2)>f(2)
∵F(x)在R上单调递增 ∴3x-x^2-2>0 x^2-3x+2<0
解得1