(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*.*(1+1/99)(1-1/99)这是六年级举一反三B版上期末测试（一)的第4题,还有上面的第3题也不会,但打不出来,最好两题都能告诉我,
2019-05-05
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*.*(1+1/99)(1-1/99)
这是六年级举一反三B版上期末测试（一)的第4题,还有上面的第3题也不会,但打不出来,最好两题都能告诉我,
优质解答
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*.*(1+1/99)(1-1/99)
=(1+1/2)(1+1/3)...(1+1/99)(1-1/2)(1-1/3)...(1-1/99)
=[3/2*4/3...100/99]*[1/2*2/3...98/99]
=100/2*1/99
=50/99
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*.*(1+1/99)(1-1/99)
=(1+1/2)(1+1/3)...(1+1/99)(1-1/2)(1-1/3)...(1-1/99)
=[3/2*4/3...100/99]*[1/2*2/3...98/99]
=100/2*1/99
=50/99