Question

tính nhanh \(S=\dfrac{1}{2}+\dfrac{1}{4}+...+\dfrac{1}{1024}\)

Answer 1

`S = 1/2 + 1/4 + ....+1/1024`

`=> 1/2S = 1/4 + 1/8 + .....+1/2048`

`=> 1/2S = 1-1/2S = ( 1/4 + 1/8 + .... + 1/2048 )-(1/2+1/4+.....+1/1024)`

`=> 1/2S = 1 - 1/2048`

`=> 1/2S = 2047/2048`

`=> S = 2047/1024` 

Answer 2

Ban lấy 2S - S là ra đáp án nhak

 

Answer 3

`S = 2047/1024` 

Cách làm `:` Bấm mày tính `bb!` 

Answer 4

ồ thì ra là thế à !

Answer 5

Đáp số:

\(\dfrac{2047}{1024}\)

Answer 6

S=12+14+....+11024S=12+14+....+11024

⇒12S=14+18+.....+12048⇒12S=14+18+.....+12048

⇒12S=1−12S=(14+18+....+12048)−(12+14+.....+11024)⇒12S=1-12S=(14+18+....+12048)-(12+14+.....+11024)

⇒12S=1−12048⇒12S=1-12048

⇒12S=20472048⇒12S=20472048

⇒S=20471024⇒S=20471024