极限问题
lim[1+1/(n+2)]^n=( ) x→∞
lim[1+1/(n+2)]^n=( ) x→∞ 解:lim[1+1/(n+2)]^n=lim[1+1/(n+2)]^(n +2)*[1+1/(n+2)]^(-2) =e
设n+2=t; 因n->无穷,故t->无穷. 于是,(n->无穷)lim[1+1/(n+2)]^n =(t->无穷)lim[(1+1/t)^(t-2)] =[(t->无穷)lim(1+1/t)^(-2)]*[(t->无穷)lim(1+1/t)^t] =[1^(-2)]*e=e。
答:因 a^n-b^n=(a-b)[a^(n-1)+a^(n-2)b+…+ab^(n-2)+b^(n-1) 当n是奇数时 令b=-c 则a^n+c^n=(a+c)[...详情>>
答:详情>>