Approximation of tan(f(n))












0












$begingroup$


I have the function $f(n)= pi (n+frac{1}{2})+epsilon frac{2pi(n+1/2)-a}{2pi(n+1/2)}$ when $epsilon<<1$, I can't understand what identity I need to use to prove that:



$tan(f(n))approx frac{2pi(n+1/2)}{epsilon(2pi(n+1/2)-a)}$
I tried with taylor but the first element in $f(x)$ taking tan function to $infty$










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  • 1




    $begingroup$
    Your function is $f(x)$, but it is written in terms of $n$. Should it be $f(n)$?
    $endgroup$
    – Calvin Godfrey
    Jan 11 at 13:28










  • $begingroup$
    What if $aapprox2pi(n+1/2)$?
    $endgroup$
    – Barry Cipra
    Jan 11 at 13:37
















0












$begingroup$


I have the function $f(n)= pi (n+frac{1}{2})+epsilon frac{2pi(n+1/2)-a}{2pi(n+1/2)}$ when $epsilon<<1$, I can't understand what identity I need to use to prove that:



$tan(f(n))approx frac{2pi(n+1/2)}{epsilon(2pi(n+1/2)-a)}$
I tried with taylor but the first element in $f(x)$ taking tan function to $infty$










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    Your function is $f(x)$, but it is written in terms of $n$. Should it be $f(n)$?
    $endgroup$
    – Calvin Godfrey
    Jan 11 at 13:28










  • $begingroup$
    What if $aapprox2pi(n+1/2)$?
    $endgroup$
    – Barry Cipra
    Jan 11 at 13:37














0












0








0





$begingroup$


I have the function $f(n)= pi (n+frac{1}{2})+epsilon frac{2pi(n+1/2)-a}{2pi(n+1/2)}$ when $epsilon<<1$, I can't understand what identity I need to use to prove that:



$tan(f(n))approx frac{2pi(n+1/2)}{epsilon(2pi(n+1/2)-a)}$
I tried with taylor but the first element in $f(x)$ taking tan function to $infty$










share|cite|improve this question











$endgroup$




I have the function $f(n)= pi (n+frac{1}{2})+epsilon frac{2pi(n+1/2)-a}{2pi(n+1/2)}$ when $epsilon<<1$, I can't understand what identity I need to use to prove that:



$tan(f(n))approx frac{2pi(n+1/2)}{epsilon(2pi(n+1/2)-a)}$
I tried with taylor but the first element in $f(x)$ taking tan function to $infty$







approximation






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share|cite|improve this question













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share|cite|improve this question








edited Jan 11 at 13:50









Jam

5,00921431




5,00921431










asked Jan 11 at 13:14









Daniel VainshteinDaniel Vainshtein

19011




19011








  • 1




    $begingroup$
    Your function is $f(x)$, but it is written in terms of $n$. Should it be $f(n)$?
    $endgroup$
    – Calvin Godfrey
    Jan 11 at 13:28










  • $begingroup$
    What if $aapprox2pi(n+1/2)$?
    $endgroup$
    – Barry Cipra
    Jan 11 at 13:37














  • 1




    $begingroup$
    Your function is $f(x)$, but it is written in terms of $n$. Should it be $f(n)$?
    $endgroup$
    – Calvin Godfrey
    Jan 11 at 13:28










  • $begingroup$
    What if $aapprox2pi(n+1/2)$?
    $endgroup$
    – Barry Cipra
    Jan 11 at 13:37








1




1




$begingroup$
Your function is $f(x)$, but it is written in terms of $n$. Should it be $f(n)$?
$endgroup$
– Calvin Godfrey
Jan 11 at 13:28




$begingroup$
Your function is $f(x)$, but it is written in terms of $n$. Should it be $f(n)$?
$endgroup$
– Calvin Godfrey
Jan 11 at 13:28












$begingroup$
What if $aapprox2pi(n+1/2)$?
$endgroup$
– Barry Cipra
Jan 11 at 13:37




$begingroup$
What if $aapprox2pi(n+1/2)$?
$endgroup$
– Barry Cipra
Jan 11 at 13:37










1 Answer
1






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oldest

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4












$begingroup$

The first step is to use



$$ tan(x +npi +pi/2) = -frac{cos x}{sin x}$$



The following is easy






share|cite|improve this answer









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    1 Answer
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    active

    oldest

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    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    4












    $begingroup$

    The first step is to use



    $$ tan(x +npi +pi/2) = -frac{cos x}{sin x}$$



    The following is easy






    share|cite|improve this answer









    $endgroup$


















      4












      $begingroup$

      The first step is to use



      $$ tan(x +npi +pi/2) = -frac{cos x}{sin x}$$



      The following is easy






      share|cite|improve this answer









      $endgroup$
















        4












        4








        4





        $begingroup$

        The first step is to use



        $$ tan(x +npi +pi/2) = -frac{cos x}{sin x}$$



        The following is easy






        share|cite|improve this answer









        $endgroup$



        The first step is to use



        $$ tan(x +npi +pi/2) = -frac{cos x}{sin x}$$



        The following is easy







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 11 at 13:33









        DamienDamien

        59714




        59714






























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