求lim(x→1)[(^3√x-1)/(x-1)]的極限.

求lim(x→1)[(^3√x-1)/(x-1)]的極限.

方法一:lim(x→1)[x^(1/3)-1]/(x-1)恰是f(x)=x^(1/3)在x=1處的導函數f'(x)=1/[3x^(2/3)]所以lim(x→1)[x^(1/3)-1]/(x-1)=f'(1)=1/3方法二:因為是0/0形式,用羅比塔法則lim(x→1)[x^(1 /3)-1]/(x-1)=lim(x→1…