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1/2=1-1/2,1/6=1/2-1/3,1/12=1/3-1/4,...计算1-1/2-1/6-1/12-1/301/2=1-1/2,1/6=1/2-1/3,1/12=1/3-1/4,...计算1-1/2-1/6-1/12-1/20-1/30少了个1/20
题目详情
1/2=1-1/2,1/6=1/2-1/3,1/12=1/3-1/4,...计算1-1/2-1/6-1/12-1/30
1/2=1-1/2,1/6=1/2-1/3,1/12=1/3-1/4,...计算1-1/2-1/6-1/12-1/20-1/30 少了个1/20
1/2=1-1/2,1/6=1/2-1/3,1/12=1/3-1/4,...计算1-1/2-1/6-1/12-1/20-1/30 少了个1/20
▼优质解答
答案和解析
1-1/2-1/6-1/12-1/30
=1-[1/2+1/2-1/3+1/3-1/4+1/30]
=1-(1-1/4+1/30)
=1-1+1/4-1/30
=1/4-1/30
=13/30
.
1-1/2-1/6-1/12-1/20-1/30
=1-[1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6]
=1-(1-1/6)
=1-1+1/6
=1/6
=1-[1/2+1/2-1/3+1/3-1/4+1/30]
=1-(1-1/4+1/30)
=1-1+1/4-1/30
=1/4-1/30
=13/30
.
1-1/2-1/6-1/12-1/20-1/30
=1-[1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6]
=1-(1-1/6)
=1-1+1/6
=1/6
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