A = 8/3.7 + 8/7.11 + 8/11.15 + … + 8/97.101

0 bình luận về “A = 8/3.7 + 8/7.11 + 8/11.15 + … + 8/97.101”

1. `A = 8/(3.7) + 8/(7.11) + … + 8/(97.101)`

   `⇒ A = 2(1/3 – 1/7 + 1/7 – 1/11 + … + 1/97 – 1/101)`

   `⇒ A = 2(1/3 – 1/101)`

   `⇒ A = 2. 98/303`

   `⇒ A = 196/303`

    

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2. $\ A = \dfrac{8}{3.7} + \dfrac{8}{7.11} + \dfrac{8}{11.15} + … + \dfrac{8}{97.101}$

   $\ = 2(\dfrac{4}{3.7} +\dfrac{4}{7.11} + \dfrac{4}{11.15} +…+\dfrac{4}{97.101})$

   `= 2(1/3 – 1/7 + 1/7 – 1/11 + 1/11 – 1/15 + … + 1/97 – 1/101)`

   `= 2(1/3 – 1/101)`

   `= 2 . 98/303`

   `= 196/303`

    Vậy `A = 196/303`

    

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