`( 1/2 + 1/4 + 1/8 + 1/16 ) : x = 1/2 + 1/6 + 1/12 + 1/20 + ... + 1/132`
`( 8/16 + 4/16 + 2/16 + 1/16 ) : x = 1/2 + 1/6 + 1/12 + 1/20 + ... + 1/132`
`15/16 : x = 1/{1 × 2} + 1/{2 × 3} + 1/{3 × 4} + 1/{4 × 5} + ... + 1/{11 × 12}`
`15/16 : x = 1/1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5 + ... + 1/11 - 1/12`
`15/16 : x = 1/1 - 1/12`
`15/16 : x = 11/12`
`x = 15/16 : 11/12`
`x = 45/44`
Vậy , `x = 45/44`
`#dtkc`