A x 2 = 1 - ( 1/2 + 1/4 + 1/8 + ..... + 1/512 + 1/1024 ) - 1/1024

A x 2 = 1 - 1/1024 + A

A x 2 - A = 1 - 1/1024

A = 1 - 1/1024 

A = 1023 /1024

A x 2 = 1 - ( 1/2 + 1/4 + 1/8 + 1/16 + ..... + 1/512 + 1/1024 ) - 1/1024

A x 2 = 1 - 1/1024 + A

A x 2 - A = 1 - 1/1024

A = 1 - 1/1024 

A = 1023 /1024

má cái ngoặc xuống là seo

1+21​+41​+81​+161​+321​+641​+...+5121​+10241​=??????????

\(< = > 1 + \frac{1}{1 \cdot 2} + \frac{1}{2 \cdot 2} + \frac{1}{2 \cdot 4} + . . . + \frac{1}{2 \cdot 256} + \frac{1}{2 \cdot 512}\)

\(< = > 1 + \frac{1}{1} - \frac{1}{2} + \frac{1}{2} - \frac{1}{2} + \frac{1}{2} - \frac{1}{4} + . . . + \frac{1}{2} - \frac{1}{256} + \frac{1}{2} - \frac{1}{512}\)

\(< = > 1 + \frac{1}{1} - \frac{1}{512}\)

\(< = > \frac{1023}{512}\)

\(1 + \frac{1}{2} + \frac{1}{4} + \frac{1}{8} + \frac{1}{16} + \frac{1}{32} + \frac{1}{64} + . . . + \frac{1}{512} + \frac{1}{1024} = ? ? ? ? ? ? ? ? ? ?\)

\(< = > 1 + \frac{1}{1 \cdot 2} + \frac{1}{2 \cdot 2} + \frac{1}{2 \cdot 4} + . . . + \frac{1}{2 \cdot 256} + \frac{1}{2 \cdot 512}\)

\(< = > 1 + \frac{1}{1} - \frac{1}{2} + \frac{1}{2} - \frac{1}{2} + \frac{1}{2} - \frac{1}{4} + . . . + \frac{1}{2} - \frac{1}{256} + \frac{1}{2} - \frac{1}{512}\)

\(< = > 1 + \frac{1}{1} - \frac{1}{512}\)

\(< = > \frac{1023}{512}\)

A=21​+41​+81​+...+5121​+10241​

\(= \frac{1}{2} + \frac{1}{2^{2}} + \frac{1}{2^{3}} + . . . + \frac{1}{2^{10}}\)

\(\Rightarrow 2 � = 1 + \frac{1}{2} + \frac{1}{2^{2}} + . . . + \frac{1}{2^{9}}\)

\(\Rightarrow 2 � - � = � = 1 - \frac{1}{2^{10}}\)

A x 2 = 1 - ( 1/2 + 1/4 + 1/8 + 1/16 + ..... + 1/512 + 1/1024 ) - 1/1024

A x 2 = 1 - 1/1024 + A

A x 2 - A = 1 - 1/1024

A = 1 - 1/1024 

A = 1023 /1024