用洛必達(dá)法測 分子分母同時(shí)求導(dǎo)
lim立方根x^2-2立方根x+1/(x-1)^2
=lim立方根x^2-lim2立方根x+lim1/(x-1)^2
=1-2+無窮大=無窮大
題目怎么看都覺得怪 目測你少打了中括號(hào)導(dǎo)致我理解錯(cuò)誤
lim[立方根x^2-2立方根x+1] / (x-1)^2
=lim [2/3 x^(-1/3) - 2/3 x^(-2/3)] / (2x-2)
=lim [-2/9 x^(-4/3) + 4/9 x^(-5/3)] / 2
=[-2/9 + 4/9] /2
=1/9