F=đã cho
=>1/2F=1/4+1/8+1/16+...+1/8192
=>F-1/2F=1/2-1/8192
=>1/2F=1/2-1/8192
=>F=1-1/4096
=>F=4095/4096
Vậy......
Ta có : \(F=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+......+\frac{1}{4096}\)
\(\Rightarrow2F=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+.....+\frac{1}{2048}\)
\(\Rightarrow2F-F=1-\frac{1}{4096}\)
\(\Rightarrow F=\frac{4095}{4096}\)