Đáp án:
`A=1/2+1/2^2+1/2^3+.......+1/2^10=1023/1024`
Giải thích các bước giải:
`A=1/2+1/2^2+1/2^3+.......+1/2^10`
`2A=1+1/2+1/2^2+...+1/2^9`
`2A-A=(1+1/2+1/2^2+...+1/2^9)-(1/2+1/2^2+1/2^3+...+1/2^10)`
`A=1+1/2+1/2^2+...+1/2^9-1/2-1/2^2-1/2^3-...-1/2^10`
`A=1+(1/2-1/2)+(1/2^2-1/2^2)+...+(1/2^9-1/2^9)-1/2^10`
`A=1-1/2^10`
`A=1-1/1024`
`A=1024/1024-1/1024`
`A=1023/1024`
