(1-1/2²)(1-1/3²)(1-1/4²)…(1-1/99²)(1-1/100²)
=(1+1/2)(1-1/2)(1+1/3)(1-1/3).(1+1/99)(1-1/100)(1+1/100)
=3/2*1/2*4/3*2/3...100/99*99/100*101/100
=(1/2)*(101/100)
=101/200
(1-1/2²)(1-1/3²)(1-1/4²)…(1-1/99²)(1-1/100²)
=(1+1/2)(1-1/2)(1+1/3)(1-1/3).(1+1/99)(1-1/100)(1+1/100)
=3/2*1/2*4/3*2/3...100/99*99/100*101/100
=(1/2)*(101/100)
=101/200