(1-2的平方分之一)(1-3的平方分之一)(1-四的平方之一)...(1-100的平方分之一)
=(1+½)(1-½)(1+1/3)(1-1/3)(1+¼)(1-¼)……(1+1/100)(1-1/100)
=(3/2)×(½)×(4/3)×(2/3)×(5/4)×(¾)×……×(101/100)×(99/100)
=(½)×(101/100)
=101/200
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)...(1-1/99)(1+1/99)(1-1/100)(1+1/100)
=1/2*3/2*2/3*4/3*...*98/99*100/99*99/100*101/100
中间的全部约分了
=1/2*101/100
=101/200
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)...(1-1/99)(1+1/99)(1-1/100)(1+1/100)
=1/2*3/2*2/3*4/3*...*98/99*100/99*99/100*101/100
=1/2*(3/2*2/3)*(4/3*3/4)*...*(99/98*98/99)*(100/99*99/100)*101/100
=1/2*101/100
=101/200