(1\5+1\7+9\1+1\11)x(1\7+1\9+1\11+1\13)-(1\5+1\7+1\9+1\11+1\13)x(1\7+1\9+1\11
问题描述:
(1\5+1\7+9\1+1\11)x(1\7+1\9+1\11+1\13)-(1\5+1\7+1\9+1\11+1\13)x(1\7+1\9+1\11
答
(1/5+1/7+1/9+1/11+1/13)*(1/7+1/9+1/11+1/13)-(1/5+1/7+1/9+1/11+1/13)*(1/7+1/9+1/11)=(1/5+1/7+1/9+1/11+1/13)*[(1/7+1/9+1/11+1/13)-(1/7+1/9+1/11)]=(1/5 + 1/7 + 1/9 + 1/11 + 1/13 )*1/13通分得到答案这是我...