分子是1-1/2+1/3-1/4+1/5-1/6……+1/99-1/100,分母有点复杂,是1/(1+101)+1/(2+102)+1/(3+103)+……+1/(50+150),我采用了通分法,裂项法算了很久都还是没能算出来,因为有一点复杂,所以算得头很晕,
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![分子是1-1/2+1/3-1/4+1/5-1/6……+1/99-1/100,分母有点复杂,是1/(1+101)+1/(2+102)+1/(3+103)+……+1/(50+150),我采用了通分法,裂项法算了很久都还是没能算出来,因为有一点复杂,所以算得头很晕,](/uploads/image/z/5317375-31-5.jpg?t=%E5%88%86%E5%AD%90%E6%98%AF1-1%2F2%2B1%2F3-1%2F4%2B1%2F5-1%2F6%E2%80%A6%E2%80%A6%2B1%2F99-1%2F100%2C%E5%88%86%E6%AF%8D%E6%9C%89%E7%82%B9%E5%A4%8D%E6%9D%82%2C%E6%98%AF1%2F%281%2B101%29%2B1%2F%282%2B102%29%2B1%2F%283%2B103%29%2B%E2%80%A6%E2%80%A6%2B1%2F%2850%2B150%29%2C%E6%88%91%E9%87%87%E7%94%A8%E4%BA%86%E9%80%9A%E5%88%86%E6%B3%95%2C%E8%A3%82%E9%A1%B9%E6%B3%95%E7%AE%97%E4%BA%86%E5%BE%88%E4%B9%85%E9%83%BD%E8%BF%98%E6%98%AF%E6%B2%A1%E8%83%BD%E7%AE%97%E5%87%BA%E6%9D%A5%2C%E5%9B%A0%E4%B8%BA%E6%9C%89%E4%B8%80%E7%82%B9%E5%A4%8D%E6%9D%82%2C%E6%89%80%E4%BB%A5%E7%AE%97%E5%BE%97%E5%A4%B4%E5%BE%88%E6%99%95%2C)
分子是1-1/2+1/3-1/4+1/5-1/6……+1/99-1/100,分母有点复杂,是1/(1+101)+1/(2+102)+1/(3+103)+……+1/(50+150),我采用了通分法,裂项法算了很久都还是没能算出来,因为有一点复杂,所以算得头很晕,
分子是1-1/2+1/3-1/4+1/5-1/6……+1/99-1/100,分母有点复杂,是1/(1+101)+1/(2+102)+1/(3+103)+……+1/(50+150),我采用了通分法,裂项法算了很久都还是没能算出来,因为有一点复杂,所以算得头很晕,
分子是1-1/2+1/3-1/4+1/5-1/6……+1/99-1/100,分母有点复杂,是1/(1+101)+1/(2+102)+1/(3+103)+……+1/(50+150),我采用了通分法,裂项法算了很久都还是没能算出来,因为有一点复杂,所以算得头很晕,
原式分子(1-1/2+1/3-1/4+……+1/99-1/100)分母1/(1+101)+1/(2+102)+……+1/(50+150)
把分子全看作是+结果就需要-去2倍的(1/2+1/4+……+1/100)
=(1+1/2+1/3+1/4+……+1/99+1/100)-2×(1/2+1/4+……+1/100)把这项乘出来
=(1+1/2+1/3+1/4+……+1/99+1/100)-(1+1/2+1/3+……+1/50)相减得到
=1/51+……+1/99+1/100
分母
=1/102+1/104+1/106+……+1/200提取1/2
=1/2 ×(1/51+……+1/99+1/100)
原式=2
是50
分子=1-1/2+1/3-1/4+1/5-1/6……+1/99-1/100
=1+1/2+1/3+1/4+1/5+1/6……+1/99+1/100-2*(1/2+1/4+1/6+......+1/100)
=1+1/2+1/3+1/4+1/5+1/6……+1/99+1/100-(1+1/2+1/3+......+1/50)
=1/51+1/52...
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分子=1-1/2+1/3-1/4+1/5-1/6……+1/99-1/100
=1+1/2+1/3+1/4+1/5+1/6……+1/99+1/100-2*(1/2+1/4+1/6+......+1/100)
=1+1/2+1/3+1/4+1/5+1/6……+1/99+1/100-(1+1/2+1/3+......+1/50)
=1/51+1/52+1/53+......+1/100
分母=1/102+1/104+1/106+......+1/200
=1/2*(1/51+1/52+1/53+......+1/100)
分子除分母=1/(1/2)=2
收起
算式图