[1-1/(11*11)]*[1-1/1(2*12)]...[1-1/(99*99)]

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[1-1/(11*11)]*[1-1/1(2*12)]...[1-1/(99*99)]

[1-1/(11*11)]*[1-1/1(2*12)]...[1-1/(99*99)]
[1-1/(11*11)]*[1-1/1(2*12)]...[1-1/(99*99)]

[1-1/(11*11)]*[1-1/1(2*12)]...[1-1/(99*99)]
=(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

[1-1/(11*11)]*[1-1/(12*12)]...[1-1/(99*99)]
=(1+1/11)(1-1/11)*(1+1/12)(1-1/12)*...[(1+1/99)(1-1/99)
=12/11*10/11*13/12*11/12*...*100/99*98/99
=10/11*100/99
=1000/1089