1/11+1/209+1/513+1/945+1/1505+1/2193

Đáp án+Giải thích các bước giải:

 `1/11 + 1/209 + 1/513 + 1/945 + 1/1505 + 1/2193`

`= 1/11 + 1/(11.19) + 1/(19.27) + 1/(27.35) + 1/(35.43) + 1/(43.51)`

`=1/11 + 1/8 . ( 1/(11.19) + 1/(19.27) + 1/(27.35) + 1/(35.43) + 1/(43.51) )`

`= 1/11 + 1/8 . ( 1/11 - 1/19 + 1/19 - 1/27 + 1/27 - 1/35 + 1/35 - 1/43 + 1/43 - 1/51 )`

 `= 1/11 + 1/8 . ( 1/11 - 1/51 )`

`= 1/11 + 1/8 . 40/561`

`= 1/11 + 4/561`

`= 56/561`