(1-1/2+1/3-1/4+1/5-1/6+.+1/99-1/100)/(1/102+1/104+1/106+.+1/200=?急
问题描述：
(1-1/2+1/3-1/4+1/5-1/6+.+1/99-1/100)/(1/102+1/104+1/106+.+1/200=?急
答
分子1-1/2+1/3-1/4+1/5-1/6+...+1/99-1/100= (1+1/3+1/5+...+1/99)-(1/2+1/4+1/6+...+1/100)= (1+1/2+1/3+1/4+1/5+1/6+...+1/99+1/100)-2×(1/2+1/4+1/6+...+1/100)= (1+1/2+1/3+1/4+1/5+1/6+...+1/99+1/100)-(1+1/2...