title: Plotting and finding roots of bessel functions
body: <p>I am trying to plot roots of a function that is composed of multiple bessel functions being added and multiplied in Matlab.  The equation is Jm(omega)*Ik(omega)+Im(omega)*Jk(omega) where Jm is the bessel function of the first kind of order m (besselj). Im is the modified bessel function of the first kind of order m (besseli).  For each mode m=o,1,2,...and n=1,2,3...  The frequency omega(mn) is the corresponding root of the listed equation. m=0,1,2 n-1,2,3,4.  I need to solve the equation for the 12 roots.  I am new to Matlab and this is a little out of my league. So far I have this code but I wasn't sure if I needed the variable omega in the script or not.  I have also looked at other people's questions on the suject but didn't see any quite like this.  The plots I have seen look nothing like mine which tells me I am probably wrong.  Thanks for any help.</p>
  
  <pre><code>m=(0:2); k=(1:3); n=(1:4);
  Jm=besselj(m,n');
  Ik=besseli(k,n');
  Jk=besselj(k,n');
  Im=besseli(m,n');
  g=Jm.*Ik+Im.*Jk
  plot(g)
  </code></pre>