Question

Tính 1/2+1/4+......+1/256=?

Answer 1

A= 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 
2A= 2(1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256) 
= 1+1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 
=>A = 2A-A =1+1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 -1/2 - 1/4 - 1/8 - 1/16 - 1/32 - 1/64 - 1/128 - 1/256 
=1-1/256 
=255/256

Answer 2

A= 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 

2A= 2(1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256) 

= 1+1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 

=>A = 2A-A =1+1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 -1/2 - 1/4 - 1/8 - 1/16 - 1/32 - 1/64 - 1/128 - 1/256 

=1-1/256 

=255/256

Answer 3

A= 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 
2A= 2(1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256) 
= 1+1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 
=>A = 2A-A =1+1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 -1/2 - 1/4 - 1/8 - 1/16 - 1/32 - 1/64 - 1/128 - 1/256 
=1-1/256 
=255/256

Answer 4

A= 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 
2A= 2(1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256) 
= 1+1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 
=>A = 2A-A =1+1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 -1/2 - 1/4 - 1/8 - 1/16 - 1/32 - 1/64 - 1/128 - 1/256 
=1-1/256 
=255/256

Answer 5

Bạn nhỏ giỏi đấy!!!!!!!!!!!!!!!

Thật sự đáng khen.

 

Answer 6

255/256

Answer 7

DUNG ROI LA 255/256

Answer 8

255/256 nha hehe

Answer 9

đúng rồi 255/256 tui thi rồi 

Answer 10

dung roi do ban a

Answer 11

255/256

Answer 12

bằng 255/256 ta có sách giải đó

Answer 13

cảm ơn các cậu nha

Answer 14

A=1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256

2*A=1+1/2+1/4+1/8+1/16+1/32+1/64+1/128

2*A-A=(1+1/2+1/4+...+1/128)-(1/2+1/4+1/8+...+1/256)

A=1-1/256=255/256

Answer 15

a ba la xi to o ba nhai nhoi a ba la 

Answer 16

255/256

Answer 17

255/256

Answer 18

A=1/2

Answer 19

bằng 255/256 nhé 

Answer 20

255/256

Answer 21

255/256

Answer 22

255/256

Answer 23

255/256 chắc chắn

Answer 24

255/256

Answer 25

255/256