(lnx)'=lim[h→0] [ln(x+h)-lnx]/h
=lim[h→0] ln[(x+h)/x]/h
=lim[h→0] ln(1+h/x)/h
ln(1+h/x)与h/x等价,用等价无穷小代换
=lim[h→0] (h/x) / h
=1/x
希望可以帮到你,如果解决了问题,请点下面的"选为满意回答"按钮,
(lnx)'=lim[h→0] [ln(x+h)-lnx]/h
=lim[h→0] ln[(x+h)/x]/h
=lim[h→0] ln(1+h/x)/h
ln(1+h/x)与h/x等价,用等价无穷小代换
=lim[h→0] (h/x) / h
=1/x
希望可以帮到你,如果解决了问题,请点下面的"选为满意回答"按钮,