1/3+1/(2*4)+1/(3*5)+1/(4+6).+1/(19*21)+1/(20*22)
来源:学生作业帮 编辑:搜狗做题网作业帮 分类:数学作业 时间:2024/07/08 08:05:54
1/3+1/(2*4)+1/(3*5)+1/(4+6).+1/(19*21)+1/(20*22)
1/3+1/(2*4)+1/(3*5)+1/(4+6).+1/(19*21)+1/(20*22)
=1/2×(1-1/3+1/.3-1/5+……1/19-1/21)+1/2×(1/2-14+1/4-1/6+……+1/20-1/22)
=1/2×20/21+1/2×10/22
=10/21+5/22
=325/462
再问: 1/3+1/(2*4)+1/(3*5)+1/(4+6)......+1/(19*21)+1/(20*22)为什么= =1/2×(1-1/3+1/.3-1/5+……1/19-1/21)+1/2×(1/2-14+1/4-1/6+……+1/20-1/22) =1/2×20/21+1/2×10/22 =10/21+5/22 =325/462
=1/2×(1-1/3+1/.3-1/5+……1/19-1/21)+1/2×(1/2-14+1/4-1/6+……+1/20-1/22)
=1/2×20/21+1/2×10/22
=10/21+5/22
=325/462
再问: 1/3+1/(2*4)+1/(3*5)+1/(4+6)......+1/(19*21)+1/(20*22)为什么= =1/2×(1-1/3+1/.3-1/5+……1/19-1/21)+1/2×(1/2-14+1/4-1/6+……+1/20-1/22) =1/2×20/21+1/2×10/22 =10/21+5/22 =325/462
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