limx->0【1/x】tanx=lim e^(tanx ln1/x)=lim e^(x ln1/x)=lim e^(ln1/x / 1/x)用洛必达 =lim e^(x*(-1/x^2) / (-1/x^2))怎么到这一步的?看不懂=lim e^x=e^0=1