title: The relative difference goes towards negative infinity when it's supposed to go towards 0
body: <p>I have written the following code to plot the velicity-courses of two different models (blue and green line) and the relative difference between them (orange line):</p>
  
  <pre><code>%% ----- Absolulte Carvelocity v[km/h] in carfixed Coordinate system ----
  %  Define Plotproperties
  figure('Position', [100, 100, 1024, 768]);
  hold on; grid on;
  title('Absolute Velocity');
  xlabel('time t[s]');
  ylabel('absolute velocity v[km/h]');
  xlim([t_start t_end]);
  
  % Calculate the difference between the models
  t = erg_sl.Vehicle.v_ms.Time;
  v_ms = reshape(erg_sl.Vehicle.v_ms.Data,1,[],1);
  diff=zeros(1,size_cmtime(2));
  for ctr=1:size_cmtime(2)
      diff(1,ctr)=-(erg_cm.Car_v.data(ctr)*3.6-v_ms(1,round(ctr*fac))*3.6)/abs(erg_cm.Car_v.data(ctr)*3.6)*100;
  end
  
  % From Carmaker
  line(erg_cm.Time.data,erg_cm.Car_v.data .* 3.6,'Color','b','LineWidth',2)
  
  % From Simulink
  line(erg_sl.Vehicle.v_ms.Time,erg_sl.Vehicle.v_ms.Data .* 3.6,'Color',[0,0.6,0.5],'LineWidth',2)
  
  % Legend
  legend('Carmaker','Simulink');
  
  % Change axes
  ax1 = gca;
  %ax1.XLim = [0 20];
  %ax1.YLim = [-15 15];
  ax2 = axes('Position',ax1.Position,'YAxisLocation','right', 'Color','none','YColor',[255,127,80]/256);
  ax2.YLim = [-30 30];
  ax2.YLabel.String = 'Relative difference [%]';
  linkaxes([ax1,ax2],'x');
  
  % Plot the difference
  line(erg_cm.Time.data,diff,'Parent',ax2,'LineWidth',2,'Color',[255,127,80]/256)
  
  % legend
  legend('Relative Abweichung','Location','South')
  
  %  ------------------------------------------------------------------------
  </code></pre>
  
  <p>Actually it works quite fine and i get this plot:
  <a href="https://i.stack.imgur.com/Ogsvj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ogsvj.png" alt="Generated Plot"></a></p>
  
  <p>Now the problem is, that in the beginning the difference is actually almost zero, but the orange line (which is the relative difference) goes towards negative infinity. You can even see that from <code>t=0</code> to <code>t~75</code> the green line is even above the blue one and so the orange one is supposed to be above 0. So what is wrong about the code, so this happens?</p>
  
  <p>EDIT: Here's another plot of the same script which looks a lot more like what I expected. The orange line heads towards <code>-inf</code>, too, but just for Divisors that are smaller than one which is logical to me:
  <a href="https://i.stack.imgur.com/dFojj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dFojj.png" alt="Plot that I expect"></a></p>