第1个回答 2010-07-28
我很想帮你算算看,可我对着屏幕发了半天呆也没看懂你写了些什么,茫然ing~~
第2个回答 2010-07-28
原式=1×1\2+1\2×1\3+1\3×1\4+1\4×1\5+1\5×1\6-1\7×1\8
=1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7-1/7+1/8
=1/2+1/2-1/7-1/7+1/8
=1-2/7+1/8
=5/7+1/8
=47/56=7/8
2.-1+2+(3-4-5+6)+(7-8-9-10)+...+(47-48-49-50)=1
第3个回答 2010-07-28
解原式=1×1\2+1\2×1\3+1\3×1\4+1\4×1\5+1\5×1\6-1\7×1\8
=1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7-1/7+1/8
=1/2+1/2-1/7-1/7+1/8
=1-2/7+1/8
=5/7+1/8
=7/8
-1+2+(3-4-5+6)+(7-8-9-10)+...+(47-48-49-50)=1
就是这个样子,我也是初一的,呵呵,这题做过!~