|
Post Closed as "too localized" by Bruce Westbury, Yemon Choi, Daniel Litt, Igor Rivin, fedja
|
||||
|
|
||||
|
3 | empiric test with a c program | ||
|
We know $\frac{1}{81}$ gives us $0.\overline{0123456790}$ How do we create a recurrent decimal with the property of repeating: $0.\overline{0123456789}$ a) Is there a method to construct such number? b) Is there a solution? c) Is the solution in $\mathbb{Q}$? Thanks! Beco Edited: According with wikipedia page: http://en.wikipedia.org/wiki/Decimal One could get this number by applying this series. Supppose: $M=123456789$, $x=10^{10}$, then $0.\overline{0123456789}= \frac{M}{x}\cdot$ $\sum$ ${(10^{-9})}^k$ $=\frac{M}{x}\cdot\frac{1}{1-10^{-9}}$ $=\frac{M}{9999999990}$ Unless my calculator is crazy, this is giving me $0.012345679$, not the expected number. Although the example of wikipedia works fine with $0.\overline{123}$. The answer that was there for some time and then deleted gave me another equation: $\frac{M}{1-10^{-10}}$. Well, that does not work either. 2nd Edition: Just to get rid of the gnome calculator, Running a simple program written in C with very large precision (long double) I get this result:
Result: $0.0123456789123456787266031042804570461158$ |
||||
|
2 | some equations I tired | ||
|
We know $\frac{1}{81}$ gives us $0.\overline{0123456790}$ How do we create a recurrent decimal with the property of repeating: $0.\overline{0123456789}$ a) Is there a method to construct such number? b) Is there a solution? c) Is the solution in $\mathbb{Q}$? Thanks! Beco Edited: According with wikipedia page: http://en.wikipedia.org/wiki/Decimal One could get this number by applying this series. Supppose: $M=123456789$, $x=10^{10}$, then $0.\overline{0123456789}= \frac{M}{x}\cdot$ $\sum$ ${(10^{-9})}^k$ $=\frac{M}{x}\cdot\frac{1}{1-10^{-9}}$ $=\frac{M}{9999999990}$ Unless my calculator is crazy, this is giving me $0.012345679$, not the expected number. Although the example of wikipedia works fine with $0.\overline{123}$. The answer that was there for some time and then deleted gave me another equation: $\frac{M}{1-10^{-10}}$. Well, that does not work either. |
||||
|
1 |
|
||

