Question

1/2+1/8+1/32+1/128+1/512

Answer 1

`1/2+1/8+1/32+1/128+1/512`

đặt `A=1/2+1/8+1/32+1/128+1/512`

`2xx A = 2xx( 1/4+1/8+1/32+1/128+1/512)`

`2xx A = 1/2+ 1/4+1/8+1/32+1/128+1/256`

`2xx A -A= (1/2+ 1/4+1/8+1/32+1/128+1/256) -(1/4+1/8+1/32+1/128+1/512)`

`A= 1/2- 1/512`

`->A=255/512`

`@ `\(BaoTran\)

Answer 2

\(=\dfrac{256+64+16+4+1}{512}\\ =\dfrac{341}{512}\)