Find a function given a limit












0












$begingroup$


I'm coding some algorithms, but I need help to find a function.
Let' suppose these 3 functions:



$$c(x)=1-g(x)$$



$$r_1(x)=frac{sqrt{2}}{2^{left(x-1right)}}$$



$$r_2(x) = frac{sqrt{2}}{2^{left(x-1right)}}cdot g(x)$$



$$d(x)=frac{r_1(x)+r_2(x)}{2}cdotfrac{1}{c(x)}$$



My need is to find the function g that allows



$$lim_{xtoinfty}d(x)=1$$



(or at least, as close as possible to 1).



My constraints:





  • Being quickly close to the limit


  • $for xin[1; 128], g(x) in [0; 1[$





I put all these functions in a graph for clarity:
https://www.desmos.com/calculator/dgkmwtgis8



My level in mathematics in not very good, so for now I just try to adapt the following functions:
$$g_1=sqrt{frac{2^x-1}{2^x}}$$
$$g_2 =frac{2^x-1}{2^x}$$



g1 works for my code, but d(x) is too far from 1.



Thank you for any help you could provide !










share|cite|improve this question











$endgroup$












  • $begingroup$
    Do you mean that $d(x)=frac{r_1(x)+r_2(x)}{2c(x)}$, and do you want $lim_{xrightarrow infty} d(x) = 1$?
    $endgroup$
    – Doyun Nam
    Feb 1 at 6:27










  • $begingroup$
    Yes, exactly. I wasn't sure how to write that. I will edit my post accordingly.
    $endgroup$
    – Ealrann
    Feb 1 at 6:30










  • $begingroup$
    I find some function $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$. when applying this $g$ at desmos calculator you made above, the $d(x)$ is identical to $1$. Please check it. And because the process to get this $g$ is a bit tedious calculation, I skipped it to write down. However If you need it, please ask me for it.
    $endgroup$
    – Doyun Nam
    Feb 1 at 6:41








  • 1




    $begingroup$
    This solution seems perfect to me ! Thank you very, very much!
    $endgroup$
    – Ealrann
    Feb 1 at 6:53










  • $begingroup$
    You should copy this equation into an answer. At least I should give you a vote :D.
    $endgroup$
    – Ealrann
    Feb 1 at 7:31
















0












$begingroup$


I'm coding some algorithms, but I need help to find a function.
Let' suppose these 3 functions:



$$c(x)=1-g(x)$$



$$r_1(x)=frac{sqrt{2}}{2^{left(x-1right)}}$$



$$r_2(x) = frac{sqrt{2}}{2^{left(x-1right)}}cdot g(x)$$



$$d(x)=frac{r_1(x)+r_2(x)}{2}cdotfrac{1}{c(x)}$$



My need is to find the function g that allows



$$lim_{xtoinfty}d(x)=1$$



(or at least, as close as possible to 1).



My constraints:





  • Being quickly close to the limit


  • $for xin[1; 128], g(x) in [0; 1[$





I put all these functions in a graph for clarity:
https://www.desmos.com/calculator/dgkmwtgis8



My level in mathematics in not very good, so for now I just try to adapt the following functions:
$$g_1=sqrt{frac{2^x-1}{2^x}}$$
$$g_2 =frac{2^x-1}{2^x}$$



g1 works for my code, but d(x) is too far from 1.



Thank you for any help you could provide !










share|cite|improve this question











$endgroup$












  • $begingroup$
    Do you mean that $d(x)=frac{r_1(x)+r_2(x)}{2c(x)}$, and do you want $lim_{xrightarrow infty} d(x) = 1$?
    $endgroup$
    – Doyun Nam
    Feb 1 at 6:27










  • $begingroup$
    Yes, exactly. I wasn't sure how to write that. I will edit my post accordingly.
    $endgroup$
    – Ealrann
    Feb 1 at 6:30










  • $begingroup$
    I find some function $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$. when applying this $g$ at desmos calculator you made above, the $d(x)$ is identical to $1$. Please check it. And because the process to get this $g$ is a bit tedious calculation, I skipped it to write down. However If you need it, please ask me for it.
    $endgroup$
    – Doyun Nam
    Feb 1 at 6:41








  • 1




    $begingroup$
    This solution seems perfect to me ! Thank you very, very much!
    $endgroup$
    – Ealrann
    Feb 1 at 6:53










  • $begingroup$
    You should copy this equation into an answer. At least I should give you a vote :D.
    $endgroup$
    – Ealrann
    Feb 1 at 7:31














0












0








0





$begingroup$


I'm coding some algorithms, but I need help to find a function.
Let' suppose these 3 functions:



$$c(x)=1-g(x)$$



$$r_1(x)=frac{sqrt{2}}{2^{left(x-1right)}}$$



$$r_2(x) = frac{sqrt{2}}{2^{left(x-1right)}}cdot g(x)$$



$$d(x)=frac{r_1(x)+r_2(x)}{2}cdotfrac{1}{c(x)}$$



My need is to find the function g that allows



$$lim_{xtoinfty}d(x)=1$$



(or at least, as close as possible to 1).



My constraints:





  • Being quickly close to the limit


  • $for xin[1; 128], g(x) in [0; 1[$





I put all these functions in a graph for clarity:
https://www.desmos.com/calculator/dgkmwtgis8



My level in mathematics in not very good, so for now I just try to adapt the following functions:
$$g_1=sqrt{frac{2^x-1}{2^x}}$$
$$g_2 =frac{2^x-1}{2^x}$$



g1 works for my code, but d(x) is too far from 1.



Thank you for any help you could provide !










share|cite|improve this question











$endgroup$




I'm coding some algorithms, but I need help to find a function.
Let' suppose these 3 functions:



$$c(x)=1-g(x)$$



$$r_1(x)=frac{sqrt{2}}{2^{left(x-1right)}}$$



$$r_2(x) = frac{sqrt{2}}{2^{left(x-1right)}}cdot g(x)$$



$$d(x)=frac{r_1(x)+r_2(x)}{2}cdotfrac{1}{c(x)}$$



My need is to find the function g that allows



$$lim_{xtoinfty}d(x)=1$$



(or at least, as close as possible to 1).



My constraints:





  • Being quickly close to the limit


  • $for xin[1; 128], g(x) in [0; 1[$





I put all these functions in a graph for clarity:
https://www.desmos.com/calculator/dgkmwtgis8



My level in mathematics in not very good, so for now I just try to adapt the following functions:
$$g_1=sqrt{frac{2^x-1}{2^x}}$$
$$g_2 =frac{2^x-1}{2^x}$$



g1 works for my code, but d(x) is too far from 1.



Thank you for any help you could provide !







limits functions






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Feb 1 at 6:35







Ealrann

















asked Feb 1 at 5:00









EalrannEalrann

32




32












  • $begingroup$
    Do you mean that $d(x)=frac{r_1(x)+r_2(x)}{2c(x)}$, and do you want $lim_{xrightarrow infty} d(x) = 1$?
    $endgroup$
    – Doyun Nam
    Feb 1 at 6:27










  • $begingroup$
    Yes, exactly. I wasn't sure how to write that. I will edit my post accordingly.
    $endgroup$
    – Ealrann
    Feb 1 at 6:30










  • $begingroup$
    I find some function $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$. when applying this $g$ at desmos calculator you made above, the $d(x)$ is identical to $1$. Please check it. And because the process to get this $g$ is a bit tedious calculation, I skipped it to write down. However If you need it, please ask me for it.
    $endgroup$
    – Doyun Nam
    Feb 1 at 6:41








  • 1




    $begingroup$
    This solution seems perfect to me ! Thank you very, very much!
    $endgroup$
    – Ealrann
    Feb 1 at 6:53










  • $begingroup$
    You should copy this equation into an answer. At least I should give you a vote :D.
    $endgroup$
    – Ealrann
    Feb 1 at 7:31


















  • $begingroup$
    Do you mean that $d(x)=frac{r_1(x)+r_2(x)}{2c(x)}$, and do you want $lim_{xrightarrow infty} d(x) = 1$?
    $endgroup$
    – Doyun Nam
    Feb 1 at 6:27










  • $begingroup$
    Yes, exactly. I wasn't sure how to write that. I will edit my post accordingly.
    $endgroup$
    – Ealrann
    Feb 1 at 6:30










  • $begingroup$
    I find some function $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$. when applying this $g$ at desmos calculator you made above, the $d(x)$ is identical to $1$. Please check it. And because the process to get this $g$ is a bit tedious calculation, I skipped it to write down. However If you need it, please ask me for it.
    $endgroup$
    – Doyun Nam
    Feb 1 at 6:41








  • 1




    $begingroup$
    This solution seems perfect to me ! Thank you very, very much!
    $endgroup$
    – Ealrann
    Feb 1 at 6:53










  • $begingroup$
    You should copy this equation into an answer. At least I should give you a vote :D.
    $endgroup$
    – Ealrann
    Feb 1 at 7:31
















$begingroup$
Do you mean that $d(x)=frac{r_1(x)+r_2(x)}{2c(x)}$, and do you want $lim_{xrightarrow infty} d(x) = 1$?
$endgroup$
– Doyun Nam
Feb 1 at 6:27




$begingroup$
Do you mean that $d(x)=frac{r_1(x)+r_2(x)}{2c(x)}$, and do you want $lim_{xrightarrow infty} d(x) = 1$?
$endgroup$
– Doyun Nam
Feb 1 at 6:27












$begingroup$
Yes, exactly. I wasn't sure how to write that. I will edit my post accordingly.
$endgroup$
– Ealrann
Feb 1 at 6:30




$begingroup$
Yes, exactly. I wasn't sure how to write that. I will edit my post accordingly.
$endgroup$
– Ealrann
Feb 1 at 6:30












$begingroup$
I find some function $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$. when applying this $g$ at desmos calculator you made above, the $d(x)$ is identical to $1$. Please check it. And because the process to get this $g$ is a bit tedious calculation, I skipped it to write down. However If you need it, please ask me for it.
$endgroup$
– Doyun Nam
Feb 1 at 6:41






$begingroup$
I find some function $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$. when applying this $g$ at desmos calculator you made above, the $d(x)$ is identical to $1$. Please check it. And because the process to get this $g$ is a bit tedious calculation, I skipped it to write down. However If you need it, please ask me for it.
$endgroup$
– Doyun Nam
Feb 1 at 6:41






1




1




$begingroup$
This solution seems perfect to me ! Thank you very, very much!
$endgroup$
– Ealrann
Feb 1 at 6:53




$begingroup$
This solution seems perfect to me ! Thank you very, very much!
$endgroup$
– Ealrann
Feb 1 at 6:53












$begingroup$
You should copy this equation into an answer. At least I should give you a vote :D.
$endgroup$
– Ealrann
Feb 1 at 7:31




$begingroup$
You should copy this equation into an answer. At least I should give you a vote :D.
$endgroup$
– Ealrann
Feb 1 at 7:31










1 Answer
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$begingroup$

If we assume $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$, then $d(x)$ is identical to $1$.






share|cite|improve this answer









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    0












    $begingroup$

    If we assume $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$, then $d(x)$ is identical to $1$.






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      If we assume $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$, then $d(x)$ is identical to $1$.






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        If we assume $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$, then $d(x)$ is identical to $1$.






        share|cite|improve this answer









        $endgroup$



        If we assume $g(x)=frac{2^x -sqrt{2}}{2^x + sqrt{2}}$, then $d(x)$ is identical to $1$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Feb 1 at 7:39









        Doyun NamDoyun Nam

        68119




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