y=lnX-2(x-1)/(x+1)求导y'=1/x-{2(x+1)-2(x-1)}/(x+1)^2 =1/x-4/(x+1)^2 =(x^2+2x-3)/x(x+1)^2得出拐点为x=1,当x=1时,y有最小值=0,x>1时,y'>0,因此这时y〉0所以x大于1时,lnX大于2(x-1)/(x+1)