1/1*3+1/3*5+……+1/99*101 Trả lời cảm ơn

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1. `1/(1*3)+1/(3*5)+……+1/(99*101)`

   `=1/2.(1 – 1/3 + 1/3 – 1/5 +….+1/99 – 1/101)`

   `=1/2.(1-1/101)`

   `=1/2.(100)/101`

   `=100/202`

   `=50/101`

   `#Study well`

    

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2. `A=1/(1\times 3)+1/(3\times 5)+……..+1/(99\times 101)`

   `2A=2/(1\times 3)+2/(3\times 5)+……..+2/(99\times 101)`

   `2A=1/1-1/3+1/3-1/5+1/5-1/7+……..+1/99-1/101`

   `2A=1-1/100=99/101`

   `A=100/101 :2=50/101`

    

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