1).f(-2)=-1,f(1)=1
f(-2)+f(1)的值=0
2).f(-2)+f(-3/2)+f(1/2)+f(1)
=log2(1/2)+log2(1/3)+log2(3)+log2(2)
=log2(1/2*1/3*3*2)
=log2(1)
=0
3).猜想f(x)+f(-1-x)=0
证明:f(x)+f(-1-x)
=log2[(x+1)/x]+log2 [(-1-x)+1]/(-1-x)
=log2 (x+1)/x+log2 x/(1+x)
=log2(1)=0
得证