(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*...*(1+1/99)*(1-1/99)(1-1/100)(1+1/100)
=(1+1/2)*(1+1/3)*...(1+1/99)(1+1/100)*(1-1/2)*(1-1/3)*...*(1-1/99)(1-1/100)(乘法交换律)
=3/2*4/3*5/4*6/5*7/6...97/96*98/97*99/98*100/99*101/100*1/2*2/3*3/4**4/5*5/6...96/97*97/98*98/99*99/100
=1/2*101*1/100
=101/200
注释:乘号用*表示