放缩法证不等式求证：3/2-1/(n+1)＜1+1/(2^2)+1/(3^2)+……+1/n^2＜2-1/n

1+1/2²+1/3²+...+1/n²
>1+1/(2×3)+1/(3×4)+...+1/[n(n+1)]
=1+(1/2-1/3)+(1/3-1/4)+...+(1/n-1/(n+1))
=1+1/2-1/3+1/3-1/4+...+1/n-1/(n+1)
=(3/2)-1/(n+1)
1+1/2²+1/3²+...+1/n²

1/(n-1)-1/n=1/n(n-1)>1/n^2>1/n(n+1)=1/n-1/(n+1)
1+1/(2^2)+1/(3^2)+……+1/n^2
<1+1/1*2+1/2*3+...+1/(n-1)n
=1+1/1-1/2+1/2-1/3+...+1/(n-1)-1/n
=2-1/n
1+1/(2^2)+1/(3^2)+……+1/n^2
>1+1...

不是我不会做。是你的分太低。