【1/(1*2)+1/(3*4)+1/(5*6)+1/(7*8)+……1/(99*100)】/(1/51+1/52+……1/100)如何巧算呀?
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![【1/(1*2)+1/(3*4)+1/(5*6)+1/(7*8)+……1/(99*100)】/(1/51+1/52+……1/100)如何巧算呀?](/uploads/image/z/66114-18-4.jpg?t=%E3%80%901%2F%281%2A2%29%2B1%2F%283%2A4%29%2B1%2F%285%2A6%29%2B1%2F%287%2A8%29%2B%E2%80%A6%E2%80%A61%2F%2899%2A100%29%E3%80%91%2F%EF%BC%881%2F51%2B1%2F52%2B%E2%80%A6%E2%80%A61%2F100%EF%BC%89%E5%A6%82%E4%BD%95%E5%B7%A7%E7%AE%97%E5%91%80%3F)
【1/(1*2)+1/(3*4)+1/(5*6)+1/(7*8)+……1/(99*100)】/(1/51+1/52+……1/100)如何巧算呀?
【1/(1*2)+1/(3*4)+1/(5*6)+1/(7*8)+……1/(99*100)】/(1/51+1/52+……1/100)
如何巧算呀?
【1/(1*2)+1/(3*4)+1/(5*6)+1/(7*8)+……1/(99*100)】/(1/51+1/52+……1/100)如何巧算呀?
把上面的分子和分母分开算好在做除运算.
先计算分子;先写出分子的通项公式
An=1/n(n+1)=1/n-1/n+1(n
分子拆项~比如三乘四分之一可以拆成三分之一减四分之一~分母不知道、、