[1-1/(11*11)]*[1-1/1(2*12)]...[1-1/(99*99)]
问题描述：
[1-1/(11*11)]*[1-1/1(2*12)]...[1-1/(99*99)]
答
=(1-1/11)(1+1/11)(1-1/12)(1+1/12)...(1-1/98)(1+1/98)(1-1/99)(1+1/99)
=(10/11)(12/11)(11/12)(13/12)...(97/98)((99/98)(98/99)(100/99)
=(10/11)(100/99)
=1000/1089