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观察下列等式:1/1x2=1-1/2,1/2x3=1/2-1/3,1/3x4=1/3-1/4,将以上三个等式两边相加得:

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/16 16:32:10
观察下列等式:1/1x2=1-1/2,1/2x3=1/2-1/3,1/3x4=1/3-1/4,将以上三个等式两边相加得:
1/1x2+1/2x3+1/3x4=1-1/2+1/2-1/3+1/3-1/4=1-1/4=3/4
(1)猜想并写出1/n(n+1)=
(2)直接写出下列各式的计算结果:1/1x2+1/2x3+1/3x4+...+1/2011x2012=
(3)探究并计算:1/1x2+1/2x3+1/3x4+...+1/n(n+1)=
1/n(n+1)=1/n-1/(n+1)
1/1x2+1/2x3+1/3x4+...+1/2011x2012
=1-1/2+1/2-1/3+1/3-1/4+……+1/2011-1/2012
=1-1/2012
=2011/2012
1/1x2+1/2x3+1/3x4+...+1/n(n+1)
=1-1/2+1/2-1/3+1/3-1/4+……+1/n-1/(n+1)
=1-1/(n+1)
=n/(n+1)