（1）y=(3x+1）^2/(x-1)
=(3x-3+2)^2/(x-1)
=9*(x-1)+4/(x-1)+12
当x>1时 y>=2*3*2+12=24
当x
求渐近线求下列曲线的水平渐近线和垂直渐近线：（1）y=(3x+1）的平方/(x-1)(2)y=ln(x-1)
（1）y=(3x+1）^2/(x-1)
=(3x-3+2)^2/(x-1)
=9*(x-1)+4/(x-1)+12
当x>1时 y>=2*3*2+12=24
当x