Solution of complicated transcendental equation












1












$begingroup$


I am trying to reproduce a result from https://arxiv.org/pdf/0811.2230.pdf Particularly, I am trying to compute the total inelasticity and make the same plot as in fig.1. However, I am unable to explicitly express $K_theta$ from eq.21, and therefore I cannot make the integral as stated in eq.22.



The transcendental equation for $K_theta$ is



$(1-K_theta)sqrt{s} = F + betasqrt{(F^2-s_p)}cos(theta) $ $qquad qquad qquad qquad $ (1)



where



$beta = sqrt{1-frac{s}{E^2}}$



$F = frac{1}{2sqrt{s}} (s + s_p - s_x) $



and



$ s=2sqrt{s} , epsilon + s_p $



$ s_p = 2delta_pE_p^2 + m_p^2 $



$ s_x = 2delta_xE_x^2 + m_x^2 $



$E_p = (1-K_theta)E$



$E_x = K_theta E$



When I plugged everything to (1) I obtained



full expresion (in this picture K means $K_theta$, this is what I want to express)



$K_theta$ is a function of $epsilon,E$ and $m_p, m_x, delta_p, delta_x$ are known constants.



I tried to solve this with Maple and Matlab by using the function solve(), but I obtained solution on several pages and further I was unable to make the integral
$int_{0}^{pi} K_theta dtheta $
Thank you very much for any help.










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$endgroup$












  • $begingroup$
    For which variable want you to solve the equation?
    $endgroup$
    – Dr. Sonnhard Graubner
    Jan 27 at 14:14










  • $begingroup$
    For the $K_theta$, so I could subsequently integrate it over $theta$
    $endgroup$
    – Tomáš
    Jan 27 at 15:02


















1












$begingroup$


I am trying to reproduce a result from https://arxiv.org/pdf/0811.2230.pdf Particularly, I am trying to compute the total inelasticity and make the same plot as in fig.1. However, I am unable to explicitly express $K_theta$ from eq.21, and therefore I cannot make the integral as stated in eq.22.



The transcendental equation for $K_theta$ is



$(1-K_theta)sqrt{s} = F + betasqrt{(F^2-s_p)}cos(theta) $ $qquad qquad qquad qquad $ (1)



where



$beta = sqrt{1-frac{s}{E^2}}$



$F = frac{1}{2sqrt{s}} (s + s_p - s_x) $



and



$ s=2sqrt{s} , epsilon + s_p $



$ s_p = 2delta_pE_p^2 + m_p^2 $



$ s_x = 2delta_xE_x^2 + m_x^2 $



$E_p = (1-K_theta)E$



$E_x = K_theta E$



When I plugged everything to (1) I obtained



full expresion (in this picture K means $K_theta$, this is what I want to express)



$K_theta$ is a function of $epsilon,E$ and $m_p, m_x, delta_p, delta_x$ are known constants.



I tried to solve this with Maple and Matlab by using the function solve(), but I obtained solution on several pages and further I was unable to make the integral
$int_{0}^{pi} K_theta dtheta $
Thank you very much for any help.










share|cite|improve this question











$endgroup$












  • $begingroup$
    For which variable want you to solve the equation?
    $endgroup$
    – Dr. Sonnhard Graubner
    Jan 27 at 14:14










  • $begingroup$
    For the $K_theta$, so I could subsequently integrate it over $theta$
    $endgroup$
    – Tomáš
    Jan 27 at 15:02
















1












1








1





$begingroup$


I am trying to reproduce a result from https://arxiv.org/pdf/0811.2230.pdf Particularly, I am trying to compute the total inelasticity and make the same plot as in fig.1. However, I am unable to explicitly express $K_theta$ from eq.21, and therefore I cannot make the integral as stated in eq.22.



The transcendental equation for $K_theta$ is



$(1-K_theta)sqrt{s} = F + betasqrt{(F^2-s_p)}cos(theta) $ $qquad qquad qquad qquad $ (1)



where



$beta = sqrt{1-frac{s}{E^2}}$



$F = frac{1}{2sqrt{s}} (s + s_p - s_x) $



and



$ s=2sqrt{s} , epsilon + s_p $



$ s_p = 2delta_pE_p^2 + m_p^2 $



$ s_x = 2delta_xE_x^2 + m_x^2 $



$E_p = (1-K_theta)E$



$E_x = K_theta E$



When I plugged everything to (1) I obtained



full expresion (in this picture K means $K_theta$, this is what I want to express)



$K_theta$ is a function of $epsilon,E$ and $m_p, m_x, delta_p, delta_x$ are known constants.



I tried to solve this with Maple and Matlab by using the function solve(), but I obtained solution on several pages and further I was unable to make the integral
$int_{0}^{pi} K_theta dtheta $
Thank you very much for any help.










share|cite|improve this question











$endgroup$




I am trying to reproduce a result from https://arxiv.org/pdf/0811.2230.pdf Particularly, I am trying to compute the total inelasticity and make the same plot as in fig.1. However, I am unable to explicitly express $K_theta$ from eq.21, and therefore I cannot make the integral as stated in eq.22.



The transcendental equation for $K_theta$ is



$(1-K_theta)sqrt{s} = F + betasqrt{(F^2-s_p)}cos(theta) $ $qquad qquad qquad qquad $ (1)



where



$beta = sqrt{1-frac{s}{E^2}}$



$F = frac{1}{2sqrt{s}} (s + s_p - s_x) $



and



$ s=2sqrt{s} , epsilon + s_p $



$ s_p = 2delta_pE_p^2 + m_p^2 $



$ s_x = 2delta_xE_x^2 + m_x^2 $



$E_p = (1-K_theta)E$



$E_x = K_theta E$



When I plugged everything to (1) I obtained



full expresion (in this picture K means $K_theta$, this is what I want to express)



$K_theta$ is a function of $epsilon,E$ and $m_p, m_x, delta_p, delta_x$ are known constants.



I tried to solve this with Maple and Matlab by using the function solve(), but I obtained solution on several pages and further I was unable to make the integral
$int_{0}^{pi} K_theta dtheta $
Thank you very much for any help.







transcendental-equations






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edited Jan 27 at 15:06







Tomáš

















asked Jan 27 at 13:07









TomášTomáš

63




63












  • $begingroup$
    For which variable want you to solve the equation?
    $endgroup$
    – Dr. Sonnhard Graubner
    Jan 27 at 14:14










  • $begingroup$
    For the $K_theta$, so I could subsequently integrate it over $theta$
    $endgroup$
    – Tomáš
    Jan 27 at 15:02




















  • $begingroup$
    For which variable want you to solve the equation?
    $endgroup$
    – Dr. Sonnhard Graubner
    Jan 27 at 14:14










  • $begingroup$
    For the $K_theta$, so I could subsequently integrate it over $theta$
    $endgroup$
    – Tomáš
    Jan 27 at 15:02


















$begingroup$
For which variable want you to solve the equation?
$endgroup$
– Dr. Sonnhard Graubner
Jan 27 at 14:14




$begingroup$
For which variable want you to solve the equation?
$endgroup$
– Dr. Sonnhard Graubner
Jan 27 at 14:14












$begingroup$
For the $K_theta$, so I could subsequently integrate it over $theta$
$endgroup$
– Tomáš
Jan 27 at 15:02






$begingroup$
For the $K_theta$, so I could subsequently integrate it over $theta$
$endgroup$
– Tomáš
Jan 27 at 15:02












1 Answer
1






active

oldest

votes


















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$begingroup$

Fist of all, Welcome to the site !.



In my humble opinion, do not waste your time. All the work is purely numerical.




  1. Generate a detailed table of $K$ as a function of $theta$

  2. Build an interpolating function

  3. Numerical integration


For the first point, starting with $theta_0=frac pi 2$ makes the problem simple and you get $K_0$. Now $theta_i=theta_{i-1}+Delta$; solve the equation starting with $K_{i-1}$ as a guess to get $K_i$ and continue. Repeat the process with new values $theta_j=theta_{j-1}-Delta$.






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    active

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    1












    $begingroup$

    Fist of all, Welcome to the site !.



    In my humble opinion, do not waste your time. All the work is purely numerical.




    1. Generate a detailed table of $K$ as a function of $theta$

    2. Build an interpolating function

    3. Numerical integration


    For the first point, starting with $theta_0=frac pi 2$ makes the problem simple and you get $K_0$. Now $theta_i=theta_{i-1}+Delta$; solve the equation starting with $K_{i-1}$ as a guess to get $K_i$ and continue. Repeat the process with new values $theta_j=theta_{j-1}-Delta$.






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      Fist of all, Welcome to the site !.



      In my humble opinion, do not waste your time. All the work is purely numerical.




      1. Generate a detailed table of $K$ as a function of $theta$

      2. Build an interpolating function

      3. Numerical integration


      For the first point, starting with $theta_0=frac pi 2$ makes the problem simple and you get $K_0$. Now $theta_i=theta_{i-1}+Delta$; solve the equation starting with $K_{i-1}$ as a guess to get $K_i$ and continue. Repeat the process with new values $theta_j=theta_{j-1}-Delta$.






      share|cite|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        Fist of all, Welcome to the site !.



        In my humble opinion, do not waste your time. All the work is purely numerical.




        1. Generate a detailed table of $K$ as a function of $theta$

        2. Build an interpolating function

        3. Numerical integration


        For the first point, starting with $theta_0=frac pi 2$ makes the problem simple and you get $K_0$. Now $theta_i=theta_{i-1}+Delta$; solve the equation starting with $K_{i-1}$ as a guess to get $K_i$ and continue. Repeat the process with new values $theta_j=theta_{j-1}-Delta$.






        share|cite|improve this answer









        $endgroup$



        Fist of all, Welcome to the site !.



        In my humble opinion, do not waste your time. All the work is purely numerical.




        1. Generate a detailed table of $K$ as a function of $theta$

        2. Build an interpolating function

        3. Numerical integration


        For the first point, starting with $theta_0=frac pi 2$ makes the problem simple and you get $K_0$. Now $theta_i=theta_{i-1}+Delta$; solve the equation starting with $K_{i-1}$ as a guess to get $K_i$ and continue. Repeat the process with new values $theta_j=theta_{j-1}-Delta$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 27 at 15:29









        Claude LeiboviciClaude Leibovici

        125k1158135




        125k1158135






























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