Question

求极限x→1 lim[ (x^m-1)/(x^n-1) ] （m,n为正整数）

Answer 1

x→1 lim[ (x^m-1)/(x^n-1) ] =x→1 lim(x-1)(x^(m-1)+x^(m-2)+……+1)/[(x-1)(x^(n-1)+x^(n-2)+……+1)=x→1 lim(x^(m-1)+x^(m-2)+……+1)/(x^(n-1)+x^(n-2)+……+1)=m/n