f(1+1)=f(1)+f(1)=4 ,f(1)=2
f(0)=0
f(0)=f(-1)+f(1)=0 ∴f(-1)=-2
∵f(-2/3)=2f(-1/3)
f(-1)=f(-1/3-2/3)=f(-1/3)+f(-2/3)=-2
所以f(-1/3)=-2/3
如果是求-1/3=f(x)的话
f(-1/3)=2f(-1/6)=-2/3
f(-1/6)=-1/3
f(1+1)=f(1)+f(1)=4 ,f(1)=2
f(0)=0
f(0)=f(-1)+f(1)=0 ∴f(-1)=-2
∵f(-2/3)=2f(-1/3)
f(-1)=f(-1/3-2/3)=f(-1/3)+f(-2/3)=-2
所以f(-1/3)=-2/3
如果是求-1/3=f(x)的话
f(-1/3)=2f(-1/6)=-2/3
f(-1/6)=-1/3