1/1*2*3+1/2*3*4+1/3*4*5~1/48*49*50=?

问题描述:

1/1*2*3+1/2*3*4+1/3*4*5~1/48*49*50=?
1个回答 分类:数学 2014-12-03

问题解答:

我来补答
1/1*2*3+1/2*3*4+1/3*4*5+.+1/48*49*50
=(1/1*2-1/2*3+1/2*3-1/3*4+1/3*4-1/4*5+……+1/48*19-1/49*50)÷2
=(1/1*2-1/49*50)÷2
=(1/2-1/2450)÷2
=1/4-1/4900
=1224/4900
=306/1225
 
 
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