1+1/3^2+1/5^2+……+1/(2n-1)^2>1+1/(3*5)+1/(5*7)+……+1/(2n-1)(2n+1)=1+(1/2)(1/3-1/5+1/5-1/7+……+1/(2n-1)-1/(2n+1))=1+(1/2)*(1/3-1/(2n+1))=(7/6)-1/2(2n+1)，n>1主要用到裂项公式：1/(a*b)=(1/(b-a))*(1/a-1/b)，a有不懂欢迎追问
