wow 60 召唤任务:求助!高手进!

来源:百度文库 编辑:神马品牌网 时间:2024/05/05 07:44:52
简算:(1+1/3+1/5+1/7)*(1/3+1/5+1/7+1/9)-(1+1/3+1/7+1/5+1/9)*(1/3+1/5+1/7)

解:(1+1/3+1/5+1/7)×(1/3+1/5+1/7+1/9)-(1+1/3+1/7+1/5+1/9)×(1/3+1/5+1/7)
=(1+1/3+1/5+1/7)×(1/3+1/5+1/7+1/9)-(1+1/3+1/7+1/5+1/9)×(1+1/3+1/5+1/7-1)
=(1+1/3+1/5+1/7)×(1/3+1/5+1/7+1/9)-(1+1/3+1/7+1/5+1/9)×(1+1/3+1/5+1/7)+(1+1/3+1/7+1/5+1/9)
=(1+1/3+1/5+1/7)[(1/3+1/5+1/7+1/9)-(1+1/3+1/7+1/5+1/9)]+(1+1/3+1/7+1/5+1/9)
=-(1+1/3+1/5+1/7)+(1+1/3+1/7+1/5+1/9)
=1/9