1.1/2>(1/2+1/4+...+1/2n)/n (n>=2)

问题描述:

1.1/2>(1/2+1/4+...+1/2n)/n (n>=2)
2.1/(n+1)(1+1/3+1/5+,+1/(2n-1))>1/n(1/2+1/4+,+1/2n) (n>=2)

(1)两边同乘n
n/2>1/2+1/4+...+1/2^n
右边分子全部用2带(如:1/4n(1-1/2)=n/2>1/2+1/4+,+1/2n(证明方法同第一小题)
得证