简算(1+1\2)*(1+1\4））*（1+1\6)*...*(1+1\10)*(1-1\3)*(1-1\5)*...*(1-1\9)急呀...

简算(1+1\2)*(1+1\4））*（1+1\6)*...*(1+1\10)*(1-1\3)*(1-1\5)*...*(1-1\9)急呀...
简算(1+1\2)*(1+1\4））*（1+1\6)*...*(1+1\10)*(1-1\3)*(1-1\5)*...*(1-1\9)
急呀...

简算(1+1\2)*(1+1\4））*（1+1\6)*...*(1+1\10)*(1-1\3)*(1-1\5)*...*(1-1\9)急呀...
(1+1/2)*(1+1/4)*(1+1/6)*...*(1+1/10)*(1-1/3)*(1-1/5)*...*(1-1/9)
=(1+1/2)*(1-1/3)*(1+1/4)*(1-1/5)(1+1/6)*(1-1/7)*(1+1/8)*(1-1/9)*(1+1/10)
=3/2*2/3*5/4*4/5*7/6*6/7*9/8*8/9*11/10
=11/10

首尾对应，有分子和分母相同可以约掉