N= $\frac{9}{1X6}$ + $\frac{9}{6X12}$ + $\frac{9}{12X18}$+……+ $\frac{9}{92X98}$

0 bình luận về “N= $\frac{9}{1X6}$ + $\frac{9}{6X12}$ + $\frac{9}{12X18}$+……+ $\frac{9}{92X98}$”

1. `N=9/ (1.6) + 9/(6.12) + 9/(12.18) + …+ 9/(92.98)`
   ` = 9/(1.6) + (9/(6.12) + 9/(12.18) + …+ 9/(92.98))`
   `  =3/2 + 9/6 . (6/(6.12) + 6/(12.18) + …+ 6/(92.98))`
   ` = 3/2 + 9/6 . (1-1/12 + 1/12 – 1/18 + … + 1/92 – 1/98)`
   ` = 3/2 + 9/6 . (1-1/98)`
   ` = 3/2 + 9/6 . 97/98`
   ` = 3/2 + 291/196`
   ` = 585/196`

   Vậy `N=585/196`

    

   Bình luận

2. Đáp án:

   `N=585/196`

   Giải thích các bước giải:

   `N=9/1.6+9/6.12+9/12.18+…+9/92.98`

   `=9/1.6+(9/6.12+9/12.18+…+9/92.98)`

   `= 3/2 + 9/6 . (1-1/12 + 1/12 – 1/18 + … + 1/92 – 1/98)`

   `= 3/2 + 9/6 . (1-1/98)`

   `=3/2+9/6*97/98`

   `=3/2+291/196`

   `=585/196`

   Bình luận