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1/1X3+1/3X5+1/5X7.+1/49X51=?1为分子,1X3为分母

题目详情
1/1X3+1/3X5+1/5X7.+1/49X51=?
1为分子,1X3为分母
▼优质解答
答案和解析
=1/2(1-1/3)-1/2(1/3-1/5)+1/2(1/5-1/7).+1/2(1/49-1/51)
=1/2(1-1/3+1/3-1/5+1/5.-1/49+1/49-1/51)
=1/2(1-1/51)
=1/2X50/51
=25/51
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