(1-1/2²)x(1-1/3²)x····x(1-1/100)
=(1-1/2)(1+1/2)(1-1/3)(1+1/3).(1-1/100)(1+1/100)
=1/2x3/2x2/3x4/3x3/4x.x99/100x101/100
=1/2x1x1x...x1x101/100
=101/200
(1-1/2²)x(1-1/3²)x····x(1-1/100)
=(1-1/2)(1+1/2)(1-1/3)(1+1/3).(1-1/100)(1+1/100)
=1/2x3/2x2/3x4/3x3/4x.x99/100x101/100
=1/2x1x1x...x1x101/100
=101/200