早教吧 育儿知识 作业答案 考试题库 百科 知识分享

lim(x→0)(n-2/n+1)^n=e^-3是怎么算来的?

题目详情
lim(x→0)(n-2/n+1)^n=e^-3是怎么算来的?
▼优质解答
答案和解析
lim(n->0) [(n-2)/(n+1)]^n
= lim(n->0) [(n+1-3)/(n+1)]^n
= lim(n->0) [1 - 3/(n+1)]^n
= lim(n->0) [1 + 1/(-(n+1)/3)]^n
= lim(n->0) [1 + 1/(-(n+1)/3)]^[-(n+1)/3) * -3/(n+1) * n]
= e^lim(n->0) -3n/(n+1)
= e^[-3lim(n->0) 1/(1+1/n)]
= e^[-3*1/(1+0)]
= e^(-3)