Question

Answer 1

b thôi ạ

Answer 2

`@Bao`

`b)=>2(2/2.4+2/4.6+2/6.8+...+2/2016.2018)`

`=>2(1/2-1/4+1/4-1/6+1/6-1/8+...+1/2016-1/2018)`

`=>2(1/2-1/2018)`

`=>2xx504/1009`

`=>1008/1009`

Answer 3

`a)3/1.4+3/4.7+...+3/40.43`

`=3(1-1/4+1/4-1/7+...+1/40-1/43)`

`=3(1-1/43)`

`=126/43`

`b)` Đặt `A=4/2.4+4/4.6+4/6.8+...+4/2016.2018`

`2A=2(1/2-1/4+1/4-1/6+...+1/2016-1/2018)`

`2A=2(1/2-1/2018)`

`A=504/1009`

Answer 4

`ttb,`

`tt{4/( 2.4)+4/(4.6)+4/(6.8)+....+4/(2016.2018)}`

`tt{=2.(2/( 2.4)+2/(4.6)+2/(6.8)+....+2/(2016.2018))}`

`tt{=2.(1/2 -1/4+1/4-1/6+....+1/2016-1/2018)}`

`tt{=2.(1/2 - 1/2018)}`

`tt{=1-1/1009}`

`tt{=1008/1009}`