y=log2(x)+logx(2x)=log2(x)+log2(2x)/log2(x)=log2(x)+(log2(x)+1)/log2(x)=log2(x)+1/log2(x)+1
令u=log2(x),则u属于R且u不等于0(因为x不等于1)则g(u)=u+1/u+1,由于u属于(-无穷,-2]U[2,+无穷）,所以值域为（-无穷,-1]U[3,+无穷]