lim(y-->0) y/ln(1+y)
=lim(y-->0)1/[1/y*ln(1+y)]
=lim(y-->0)1/[ln(1+y)^(1/y)]
=lim(t--->∞)1/[ln(1+1/t)^t] 【令1/y=t】
=1/e分子y的倒数1/y怎么成了指数了？分母不是乘以1/y?对数运算法则 b*log(a)x=log(a)x^b