(1-1/2^2)*(1-1/3^)*(1-1/4^)*……*(1-1/99^2)*(1-1/100^2)
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)*.....(1-1/99)(1+1/99)(1-1/100)(1+1/100)(平方差因式分解)
=(1/2)*(3/2)(2/3)*(4/3)*.....(98/99)*(100/99)(99/100)(101/100)
=(1/2)*(101/100)
=101/200
(1-1/2^2)*(1-1/3^)*(1-1/4^)*……*(1-1/99^2)*(1-1/100^2)
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)*.....(1-1/99)(1+1/99)(1-1/100)(1+1/100)(平方差因式分解)
=(1/2)*(3/2)(2/3)*(4/3)*.....(98/99)*(100/99)(99/100)(101/100)
=(1/2)*(101/100)
=101/200