下面的高数题目怎么做

显示全部楼层 · 2012-12-11 12:08:13

10. ∵(2^n-1)/(3^n-1)=[(2/3)^n-(1/3)^n]/[1-(1/3)^n]
∴极限为：(0-0)/(1-0)=08. ∵[根号(5x-4)-根号x]/(x-1)
=[根号(5x-4)-根号x][根号(5x-4)+根号x]/[(x-1)[根号(5x-4)+根号x]]
=(4x-4)/[(x-1)[根号(5x-4)+根号x]]
=4/[根号(5x-4)+根号x]
∴极限为：4/(1+1)=2望采纳！有问题请追问！...

千问 · 2012-12-11 12:08:13

lin(n→ ∞)(2^n-1)/(3^n-1)=lin(n→ ∞)[(2/3)^n-1/3^n]/(1-1/3^n)=lin(n→ ∞)[(2/3)^n-1/3^n]/lin(n→ ∞)(1-1/3^n)=(0-0)/(1-0)=0 lin(n→ 1)[√( 5x-4)-√x]/(x-1)=lin(n→ ∞)(5x-4-x)/(x-1)√( 5...

千问 · 2012-12-11 12:08:13

分子分母同时除以3^n，然后n的无穷大就得2/3...