title: Overbar in annotation textbox in Matlab plot (using Latex as interpreter)
body: <p>I am trying to do write a simple equation of a plane plus the value of the coefficient \bar{a}_1, a_2 and a_3 but I cannot get the \bar to work. Any suggestion? I tried $\bar{a}_{1}$ with or without dollars, everything else looks fine to me, I used latex or tex interpreter but it  cannot recognize it. this is the code:</p>
  
  <pre><code>a1=1
  a2=2
  a3=3
  str = {'LLSQ fit:','z=$\bar{a}_{1}$+a_2x+a_3y',sprintf('$\bar{a}_{1}$=%5.2f',a1),sprintf('a_2=%5.2f',a2),sprintf('a_3=%5.2f',a3)};
  annH = annotation('textbox',[0.63 0.8 0.08 0.08],'string',str,'interpreter','latex')
  set(annH,'FitBoxToText','on','fontsize', 18,'BackgroundColor',[1 1 1])  
  </code></pre>
  
  <p>thanks</p>