问题标题:
f(n)=1/(n+1)+1/(n+2)+1/(n+3)+……+1/(2n),(n∈N+),f(k+1)-f(k)=重要的是过程……
问题描述:
f(n)=1/(n+1)+1/(n+2)+1/(n+3)+……+1/(2n),(n∈N+),f(k+1)-f(k)=
重要的是过程……
沈均毅回答:
f(k+1)=1/(k+1+1)+1/(k+1+2)+1/(k+1+3)+……+1/(2k)+1/(2k+1)+1/(2(k+1))
f(k)=1/(k+1)+1/(k+2)+1/(k+3)+……+1/(2k)
等号两边分别相减
f(k+1)-f(k)=1/(2k+1)+1/(2(k+1))-1/(k+1)
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