lim2^3n-3^(2n+1)/2^3n+3^2n趋近无穷大等于多少

问题描述:

lim2^3n-3^(2n+1)/2^3n+3^2n趋近无穷大等于多少

lim(8^n-3*9^n)/(8^n+9^n)
=lim[(8/9^n-3)]/[(8/9^n+1) 2n趋近无穷大(8/9)^n趋近0
=-3