神马品牌网线雕鼻有什么副作用:初二数学
来源：百度文库 编辑：神马品牌网 时间：2024/05/10 08:47:40
1/x(x+1) + 1/(x+1)(x+2) + ......+ 1/(x+4)(x+5) 怎样简便计算
1/x(x+1) + 1/(x+1)(x+2) + ......+ 1/(x+4)(x+5)
={(1/x)-[1/(x+1)]}+……+{[1/(x+4)]-[1/(x+5)]}
=(1/x)- [1/(x+5)]
=5/x(x+5)
+ 1/(x+1)(x+2) + ......+ 1/(x+4)(x+5)=[1/x-1/(x+1)]-[1/x-2/(x+1)]-[2/x-3/(x+1)]-[3/x-4/(x+1)]-[4/x-5/(x+1)]=1/x-5/(x+1)=5/x(x+5)
1/x(x+1) + 1/(x+1)(x+2) + ......+ 1/(x+4)(x+5)
={(1/x)-[1/(x+1)]}+……+{[1/(x+4)]-[1/(x+5)]}
=(1/x)- [1/(x+5)]
=5/x(x+5)
[1/x-1/(x+1)}+……[1/(x+4)-1/(x+5)]