a(k)=1/C(n,k),k=0,1,2,...,n,当n->∞时Σa(k)得多少?
问题描述:
a(k)=1/C(n,k),k=0,1,2,...,n,当n->∞时Σa(k)得多少?
答
a(0)=a(n)=1,a(1)=a(n-1)=1/n,
a(k)=1/C(n,k)因此0于是2n趋于无穷时极限是2.