lim (1+…+1/2^n)/(1+…+1/3^n)
=lim 1(1-1/2^(n+1))/(1-1/2) / 1(1-1/3^(n+1))/(1-1/3)
=1/(1/2) / 1/(2/3)
=2/(3/2)
=4/3
有不懂欢迎追问